@article{Ribeiro2021,

title = {Light field image quality enhancement by a lightweight deformable deep learning framework for intelligent transportation systems},

author = {D A Ribeiro and J C Silva and R Lopes Rosa and M Saadi and S Mumtaz and L Wuttisittikulkij and D Zegarra Rodríguez and S Al Otaibi},

url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-85105442390&doi=10.3390%2felectronics10101136&partnerID=40&md5=749e6e9e970b9dcd5d2f325230d81d6e},

doi = {10.3390/electronics10101136},

issn = {20799292},

year  = {2021},

date = {2021-01-01},

journal = {Electronics (Switzerland)},

volume = {10},

number = {10},

publisher = {MDPI AG},

abstract = {Light field (LF) imaging has multi-view properties that help to create many applications that include auto-refocusing, depth estimation and 3D reconstruction of images, which are required particularly for intelligent transportation systems (ITSs). However, cameras can present a limited angular resolution, becoming a bottleneck in vision applications. Thus, there is a challenge to incorporate angular data due to disparities in the LF images. In recent years, different machine learning algorithms have been applied to both image processing and ITS research areas for different purposes. In this work, a Lightweight Deformable Deep Learning Framework is implemented, in which the problem of disparity into LF images is treated. To this end, an angular alignment module and a soft activation function into the Convolutional Neural Network (CNN) are implemented. For performance assessment, the proposed solution is compared with recent state-of-the-art methods using different LF datasets, each one with specific characteristics. Experimental results demonstrated that the proposed solution achieved a better performance than the other methods. The image quality results obtained outperform state-of-the-art LF image reconstruction methods. Furthermore, our model presents a lower computational complexity, decreasing the execution time. © 2021 by the authors. Licensee MDPI, Basel, Switzerland.},

note = {cited By 0},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Parnianifard2021a,

title = {Hybrid Metamodeling/Metaheuristic Assisted Multi-Transmitters Placement Planning},

author = {A Parnianifard and M Saadi and M Pengnoo and M A Imran and S A Otaibi and P Sasithong and P Vanichchanunt and T Polysuwan and L Wuttisittikulkij},

url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-85103681823&doi=10.32604%2fcmc.2021.015730&partnerID=40&md5=018d1ffb05689c57d0de306fb6af8c0f},

doi = {10.32604/cmc.2021.015730},

issn = {15462218},

year  = {2021},

date = {2021-01-01},

journal = {Computers, Materials and Continua},

volume = {68},

number = {1},

pages = {569-587},

publisher = {Tech Science Press},

abstract = {With every passing day, the demand for data traffic is increasing, and this urges the research community not only to look for an alternating spectrum for communication but also urges radio frequency planners to use the existing spectrum efficiently. Cell sizes are shrinking with every upcoming communication generation, which makes base station placement planning even more complex and cumbersome. In order tomake the next-generation cost-effective, it is important to design a network in such a way that it utilizes the minimum number of base stations while ensuring seamless coverage and quality of service. This paper aims at the development of a new simulation-based optimization approach using a hybrid metaheuristic and metamodel applied in a novel mathematical formulation of the multi-transmitter placement planning (MTPP) problem. We first develop a new mathematical programming model for MTPP that is flexible to design the locations for any number of transmitters. To solve this constrained optimization problem, we propose a hybrid approach using the radial basis function (RBF) metamodel to assist the particle swarm optimizer (PSO) by mitigating the associated computational burden of the optimization procedure.We evaluate the effectiveness and applicability of the proposed algorithm by simulating the MTPP model with two, three, four and five transmitters and estimating the Pareto front for optimal locations of transmitters. The quantitative results show that almost maximum signal coverage can be obtained with four transmitters; thus, it is not a wise idea to use higher number of transmitters in the model. Furthermore, the limitations and future works are discussed. © 2021 Tech Science Press. All rights reserved.},

note = {cited By 0},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Parnianifard2021,

title = {Robust tuning and sensitivity analysis of stochastic integer and fractional-order PID control systems: application of surrogate-based robust simulation-optimization},

author = {A Parnianifard and M Fakhfakh and M Kotti and A Zemouche and L Wuttisittikulkij},

url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-85096759809&doi=10.1002%2fjnm.2835&partnerID=40&md5=4a802eb2a671adf258784dedefd5dc07},

doi = {10.1002/jnm.2835},

issn = {08943370},

year  = {2021},

date = {2021-01-01},

journal = {International Journal of Numerical Modelling: Electronic Networks, Devices and Fields},

volume = {34},

number = {2},

publisher = {John Wiley and Sons Ltd},

abstract = {This paper aims to make a trade-off between performance and robustness in stochastic control systems with probabilistic uncertainties. For this purpose, we develop a surrogate-based robust simulation-optimization approach for robust tuning and analyzing the sensitivity of stochastic controllers. Kriging surrogate is combined with robust design optimization to construct a robust simulation-optimization model in the class of dual response surfaces. Randomness in simulation experiments due to uncertainty is analyzed through bootstrapping technique by computing confidence regions for the estimation of Pareto frontier. Results confirmed a proper trade-off between the model's performance with the measure of expected Integral Squared Error (ISE) and robustness against uncertainty in the plant's physical parameters. Finally, the proposed method is evaluated in terms of accuracy, computational cost, and simplicity particularly in comparison with some common existed techniques in the tuning of the Proportional-Integral-Derivative (PID) and Fractional-Order PID (FOPID) controllers. © 2020 John Wiley & Sons Ltd},

note = {cited By 1},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Militani2021,

title = {Enhanced routing algorithm based on reinforcement machine learning—a case of voip service},

author = {D R Militani and H P de Moraes and R L Rosa and L Wuttisittikulkij and M A Ramírez and D Z Rodríguez},

url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-85099277606&doi=10.3390%2fs21020504&partnerID=40&md5=fbe6b5946359ac954d77e82de5b162a7},

doi = {10.3390/s21020504},

issn = {14248220},

year  = {2021},

date = {2021-01-01},

journal = {Sensors (Switzerland)},

volume = {21},

number = {2},

pages = {1-32},

publisher = {MDPI AG},

abstract = {The routing algorithm is one of the main factors that directly impact on network perfor-mance. However, conventional routing algorithms do not consider the network data history, for instances, overloaded paths or equipment faults. It is expected that routing algorithms based on machine learning present advantages using that network data. Nevertheless, in a routing algorithm based on reinforcement learning (RL) technique, additional control message headers could be re-quired. In this context, this research presents an enhanced routing protocol based on RL, named e-RLRP, in which the overhead is reduced. Specifically, a dynamic adjustment in the Hello message interval is implemented to compensate the overhead generated by the use of RL. Different network scenarios with variable number of nodes, routes, traffic flows and degree of mobility are implemented, in which network parameters, such as packet loss, delay, throughput and overhead are obtained. Additionally, a Voice-over-IP (VoIP) communication scenario is implemented, in which the E-model algorithm is used to predict the communication quality. For performance comparison, the OLSR, BATMAN and RLRP protocols are used. Experimental results show that the e-RLRP reduces network overhead compared to RLRP, and overcomes in most cases all of these protocols, considering both network parameters and VoIP quality. © 2021 by the authors. Licensee MDPI, Basel, Switzerland.},

note = {cited By 1},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Saadi2020,

title = {IoT Enabled Quality of Experience Measurement for Next Generation Networks in Smart Cities},

author = {M Saadi and M T Noor and A Imran and W T Toor and S Mumtaz and L Wuttisittikulkij},

url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-85085475478&doi=10.1016%2fj.scs.2020.102266&partnerID=40&md5=e4bd4e0f5101dca2c9de5085fd3c3005},

doi = {10.1016/j.scs.2020.102266},

issn = {22106707},

year  = {2020},

date = {2020-01-01},

journal = {Sustainable Cities and Society},

volume = {60},

publisher = {Elsevier Ltd},

abstract = {Total internet traffic has witnessed unprecedented growth over the last two decades and this exponential trend is projected to continue. Future cities are expected to be smart and billions of devices will be connected forming a network. The emergence of the Internet of Things proffers to link sensors enabled digital devices with the internet thus offering new services in the context of smart cities. In this regard, it is crucial for the internet service providers (ISPs) to observe/monitor their end-to-end network performance and identify any possible service degradation(s) as the goal of smart cities can only be realized through good quality internet. In this paper, we demonstrate our hardware-software co-designed quality of experience (QoE) management solution for ISPs. Our system is capable of monitoring and reporting the web, video, VoIP, IPTV, and WiFi QoE at various network levels. We experimentally tested our solution at appropriate network locations and demonstrated QoE and latency results for one of the leading ISP of South Asia. Our solution enables the ISPs to remotely monitor the quality of their network and identify any issue(s) which can lower the customer's QoE. As the internet is the backbone of smart cities, we believe our proposed solution for QoE will help expedite the smart cities’ infrastructure and solutions. © 2020},

note = {cited By 7},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Sasithong2020a,

title = {Maximizing double-link failure recovery of over-dimensioned optical mesh networks},

author = {P Sasithong and L Q Quynh and P Saengudomlert and P Vanichchanunt and N H Hai and L Wuttisittikulkij},

url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-85074776400&doi=10.1016%2fj.osn.2019.100541&partnerID=40&md5=ff2d125f33d9c33a07daba77f93978d0},

doi = {10.1016/j.osn.2019.100541},

issn = {15734277},

year  = {2020},

date = {2020-01-01},

journal = {Optical Switching and Networking},

volume = {36},

publisher = {Elsevier B.V.},

abstract = {Double-link failure models, in which any two links in the network fail in an arbitrary order, are becoming critical in survivable optical network designs. Optical networks that are over-dimensioned and purposely preplanned for full protection against any single-link failure may not survive well in an event of a double-link failure. It is therefore important to understand how much impact a subsequent second link failure may have upon traffic recovery of both failed links. This paper primarily aims to investigate traffic recoverability when a double-link failure occurs. We propose several methods for improving traffic recovery without using additional backup capacities other than the existing backup resources available for single-link failure recovery. In each proposed method, integer linear programming formulation is derived to optimize the backup resource allocation. Numerical results on various network configurations have shed some light on how network operators can choose one of five alternative methods to better handle a double-link failure. From numerical results, Method 1 offers some improvement on the traffic recoverability of the second failed link without disturbing the recovered traffic of the first failed link. Method 2 reveals that the traffic recoverability of the first failed link can be improved if the backup routes of the unrecovered traffic of the first failed link can be reassigned. Method 3 is useful for maximizing the traffic recoverability of the first failed link. Method 4 further increases the recoverability of the second failed link while maintaining the same recoverability of the first failed link as Method 3. Finally, Method 5 accomplishes the maximum overall traffic recoverability. © 2019},

note = {cited By 2},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Parnianifard2020,

title = {A new approach for low-dimensional constrained engineering design optimization using design and analysis of simulation experiments},

author = {A Parnianifard and R Chancharoen and G Phanomchoeng and L Wuttisittikulkij},

url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-85098204649&doi=10.2991%2fijcis.d.201014.001&partnerID=40&md5=e25129019727ef10bd37479c71e7a2fd},

doi = {10.2991/ijcis.d.201014.001},

issn = {18756891},

year  = {2020},

date = {2020-01-01},

journal = {International Journal of Computational Intelligence Systems},

volume = {13},

number = {1},

pages = {1663-1678},

publisher = {Atlantis Press},

abstract = {The number of function evaluations in many industrial applications of simulation-based optimization problems is strictly limited. Therefore, only little analytical information on objective and constraint functions is available. This paper presents an adaptive algorithm called the Surrogate-Based Constrained Global-Optimization (SCGO) method to solve black-box constrained simulation-based optimization problems involving computationally expensive objective function and inequality constraints. Firstly, Kriging surrogate is constructed over a new overall objective function (called loss function) to approximate the behavior of a true model. Then, an adaptive approach is provided to improve the optimal results sequentially while enforcing a feasible solution. The SCGO method is tested on several classical engineering design problems namely design of a tension/compression spring, design of a welded beam, design of a pressure vessel, and three-bar truss design. The results demonstrate that SCGO has advantages in solving the costly constrained problems and needs less costly function evaluations. Optimization results prove that the proposed algorithm is very competitive compared to the state-of-the-art metaheuristic algorithms. © 2020 The Authors. Published by Atlantis Press B.V.},

note = {cited By 0},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Parnianifard2020a,

title = {Robust simulation-optimization of dynamic-stochastic production/inventory control system under uncertainty using computational intelligence},

author = {A Parnianifard and A Zemouche and M A Imran and L Wuttisittikulkij},

url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-85091651355&doi=10.5267%2fj.uscm.2020.9.002&partnerID=40&md5=a17252f5e80a3d578f8c9c49759e553d},

doi = {10.5267/j.uscm.2020.9.002},

issn = {22916822},

year  = {2020},

date = {2020-01-01},

journal = {Uncertain Supply Chain Management},

volume = {8},

number = {4},

pages = {633-648},

publisher = {Growing Science},

abstract = {In production/inventory control systems, the goal of the controller is to generate sophisticated decisions by controlling the order rate and inventory level. This paper aims at modeling a dynamic-stochastic production/inventory control system under two sources of variability (uncertainty) including uncertainties on demand rate and frustrating rate. The study deals with obtaining a robust optimal design of a Proportional-Integral-Derivative (PID) controller in in the stochastic control system. For this purpose, a new robust simulation-optimization method in the class of computational intelligence is proposed. To cope with the unknown distribution of uncertainty, the crossing weighted uncertainty scenarios are combined with the proposed method. Within this study, a new sequential robust efficient global optimization is proposed to make a trade-off between optimal and robustness terms in final optimization results. Finally, a numerical case with simulation experiments is conducted to demonstrate the advantages of the proposed policy in terms of optimal result, robustness, and computational cost. © 2020 by the authors; licensee Growing Science.},

note = {cited By 0},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Ullah2020,

title = {Deep learning image-based defect detection in high voltage electrical equipment},

author = {I Ullah and R U Khan and F Yang and L Wuttisittikulkij},

url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-85077793091&doi=10.3390%2fen13020392&partnerID=40&md5=e709a8d6fdbd35bfea69a3ddbe00d07b},

doi = {10.3390/en13020392},

issn = {19961073},

year  = {2020},

date = {2020-01-01},

journal = {Energies},

volume = {13},

number = {2},

publisher = {MDPI AG},

abstract = {The increase in the internal temperature of high voltage electrical instruments is due to a variety of factors, particularly, contact problems; environmental factors; unbalanced loads; and cracks in the high voltage current transformers, voltage transformers, insulators, or terminal junctions. This increase in the internal temperature can cause unusual disturbances and damage to high voltage electrical equipment. Therefore, early prevention measures of thermal anomalies in equipment are necessary to prevent high voltage equipment failure that might shut down the whole grid system. In this article, we propose a novel non-destructive approach to defect analysis in high voltage equipment by taking advantage of the infrared thermography and the deep learning (DL) approach from the machine learning paradigm. The infrared images of the components were captured using the FLIR T630 without disturbing the operations of the power grid. In the first stage, rich features maps from the convolutional layers of the AlexNet pretrained model were extracted. After feature extraction, the random forest (RF) and support vector machines (SVM) were trained for learning of the defective and non-defective high voltage electrical equipment. In an experimental analysis, the RF optimally learned the separation between defective and non-defective equipment with greater than 96% accuracy, outperforming all the other comparative approaches for deep and nondeep features. The proposed approach based on the RF is reliable and shows its efficacy for fault detection in high voltage electrical equipment. © 2020 by the authors.},

note = {cited By 7},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Pengnoo2020,

title = {Digital Twin for Metasurface Reflector Management in 6G Terahertz Communications},

author = {M Pengnoo and M T Barros and L Wuttisittikulkij and B Butler and A Davy and S Balasubramaniam},

url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-85087805599&doi=10.1109%2fACCESS.2020.3003734&partnerID=40&md5=49919922206f591d2dd98103eb7e1f6b},

doi = {10.1109/ACCESS.2020.3003734},

issn = {21693536},

year  = {2020},

date = {2020-01-01},

journal = {IEEE Access},

volume = {8},

pages = {114580-114596},

publisher = {Institute of Electrical and Electronics Engineers Inc.},

abstract = {The performance demands from data-intensive applications, such as multimedia streaming, as well as the growing number of devices connecting to the Internet, will increase the need for higher capacity wireless communication links. The research community has recently explored regions of the spectrum, including the Terahertz band (0.1 THz to 10 THz), that are underutilised for communications. THz frequencies come with a plethora of special challenges, one of which is the very narrow effective beam, thereby requiring a Line of Sight (LoS) between sender and receiver. Researchers have explored the use of reflectors that can redirect beams around blockages. In this paper, we propose a THz signal guidance system where a Digital Twin is used to model, predict and control the signal propagation characteristics of an indoor space. Our approach finds the best THz signal path from the base station to the mobile target via the tunable metamaterial walls, avoiding obstacles as needed, using geometric (ray tracing), path loss and Terahertz Potential Field (THzPF) models. With this knowledge, the digital twin guides the selection of antenna strips at a base station and the reflectors along the signal path. A top-view camera, with advanced image processing, provides context updates (obstacle and mobile target locations) to the digital twin. The image processing system also senses factors like water vapour concentration, and the material composition and surface roughness of obstacles. Such factors affect propagation strength, and the digital twin modifies the beam paths to adapt. Simulation results have shown the efficiency of our control system to maintain a reliable signal connection while minimising the use of antenna and reflector strips. Our system is the first proposal that maximises THz signal-to-noise ratio (SNR) through such a dynamic and robust control system, which integrates image processing of a room with base station configuration. © 2013 IEEE.},

note = {cited By 5},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Saadi2020a,

title = {A comparative study of customer preferences for telecommunication technologies in pakistan},

author = {M Saadi and R Manzoor and W T Toor and S K Wijayasekara and F Masood and L Wuttisittikulkij},

url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-85086277856&doi=10.4186%2fej.2020.24.3.129&partnerID=40&md5=b25e586da9849d39fcad07b67b1ba0ec},

doi = {10.4186/ej.2020.24.3.129},

issn = {01258281},

year  = {2020},

date = {2020-01-01},

journal = {Engineering Journal},

volume = {24},

number = {3},

pages = {129-136},

publisher = {Chulalongkorn University, Faculty of Fine and Applied Arts},

abstract = {The telecommunication industry is a huge and ever-growing industry and it is contributing dominantly to the economy in terms of revenue generation and being one of the biggest taxpayers to the government. Telecommunication is now considered to be a basic necessity. In this paper, a study has been conducted to know the customer preferences of telecommunication technologies in Lahore, Pakistan, and also to compare different customer preferences for telecommunication technologies. From the results of our study, we have concluded that there is a great variation among people in terms of their usage of mobile phones and internet services. Furthermore, results regarding the relationship between the socio-demographic characteristics and the preference towards specific telephony and internet service providers have also been analyzed. This work is unique when the scenario of Pakistan is considered. No such study has been conducted in Pakistan to know the customer preferences in Pakistan. Some recommendations for the telecommunication operators have also been discussed which can help to know their customer needs in a better fashion. © 2020, Chulalongkorn University, Faculty of Fine and Applied Arts. All rights reserved.},

note = {cited By 0},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Phanomchoeng2020,

title = {Hardware software co-design of a farming robot},

author = {G Phanomchoeng and M Saadi and P Sasithong and J Tangmongkhonsuk and S K Wijayasekara and L Wuttisittikulkij},

url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-85079468984&doi=10.4186%2fej.2020.24.1.199&partnerID=40&md5=424a4a5fe19cf6baadebfa4555b9bbed},

doi = {10.4186/ej.2020.24.1.199},

issn = {01258281},

year  = {2020},

date = {2020-01-01},

journal = {Engineering Journal},

volume = {24},

number = {1},

pages = {199-208},

publisher = {Chulalongkorn University, Faculty of Fine and Applied Arts},

abstract = {Food means life and no one can think about living without food. This is the most fundamental human necessity and food security is one of the major global concern of this century. With the revolution and recent advancements in the field of electronics and communication, there has been a paradigm shift from conventional farming ways to the modern one. This paper talks about the development of hardware software co-design of agricultural farming robot. Our developed farming robot has two parts namely hardware part which further consists of mechanical, electrical, control and tools segments and the software part which allows user to interact with the farming robot via cloud service. Our proposed hardware architecture is compatible with commercial Farmbot product and the developed web-based software can be extended for more features and applications. Furthermore, the developed robot has been tested and it works well. © 2020, Chulalongkorn University, Faculty of Fine and Applied Arts. All rights reserved.},

note = {cited By 1},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Wjayasekara2020,

title = {Frame size analysis of optimum dynamic tree in RFID systems},

author = {S K Wjayasekara and M Saadi and W Srichavengsup and R Anuur and S Nakpeerayuth and H -Y Hsieh and L Wuttisittikulkij},

url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-85079462637&doi=10.4186%2fej.2020.24.1.239&partnerID=40&md5=26b7fbbb08e04ffb53d6a21494e8cafe},

doi = {10.4186/ej.2020.24.1.239},

issn = {01258281},

year  = {2020},

date = {2020-01-01},

journal = {Engineering Journal},

volume = {24},

number = {1},

pages = {239-248},

publisher = {Chulalongkorn University, Faculty of Fine and Applied Arts},

abstract = {In RFID (Radio Frequency Identification) system, an anti-collision algorithm plays a prominent role in the tag recognition process to reduce the required time for identifying the tag and enhance the RFID system efficiency. In this paper, we present a theoretical analysis of optimal frame size assignment for the maximization of system efficiency of a tree-based anti-collision algorithm, called optimum dynamic tree (ODT) algorithm, which is used for RFID tag recognition process. Analysis indicates that the appropriate frame size for a given number of competing tags should not be set equal to the number of tags, which is usually adopted in literature. Instead of this, the frame size should be kept smaller roughly by a factor of 0.871 to maximize system efficiency. The closed-form solution for calculating system efficiency has been derived. The simulated results show excellent correlation with the theoretical one. Range for the exact appropriate frame sizes for the number of tags is from 2 to 100. Comparison has been made for the tag-identification time of conventional binary tree and ODT algorithms according to the international standard ISO 18000-6B. © 2020, Chulalongkorn University, Faculty of Fine and Applied Arts. All rights reserved.},

note = {cited By 1},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Saadi2019a,

title = {Visible Light communication - The Journey so Far},

author = {M Saadi and L Wuttisittikulkij},

url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-85064441106&doi=10.1515%2fjoc-2017-0107&partnerID=40&md5=cf80faf13129bd95f7cf06cd76f92400},

doi = {10.1515/joc-2017-0107},

issn = {01734911},

year  = {2019},

date = {2019-01-01},

journal = {Journal of Optical Communications},

volume = {40},

number = {4},

pages = {447-453},

publisher = {De Gruyter},

abstract = {An unprecedented demand for connecting physical objects with the internet expedites the realization of internet of things, thus creating new challenges to explore new spectrums which are suitable for communication. Visible light communication (VLc) is one promising candidate not only to remove the spectrum crunch issues but also to offer virtually unlimited, unregulated spectrum. This paper discusses how VLc can help solving spectrum crunch, non-availability issues of radio frequency spectrum and how readily available spectrum of VLc can be utilized to cope up with the bandwidth requirements of next-generation networks. Furthermore, this paper also lists the technological innovations in the area of VLc from early days till present and its possible applications in various domains. © 2019 Walter de Gruyter GmbH, Berlin/Boston 2019.},

note = {cited By 6},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Wijayasekara2019,

title = {A fast tag identification anti-collision algorithm for RFID systems},

author = {S K Wijayasekara and S Nakpeerayuth and R Annur and H -Y Hsieh and T Sanguankotchakorn and K Sandrasegaran and W Srichavengsup and T Phromsa-ard and L Wuttisittikulkij},

url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-85070777695&doi=10.1002%2fdac.4108&partnerID=40&md5=24694896b0ce2ce8535297d1bdd6a97b},

doi = {10.1002/dac.4108},

issn = {10745351},

year  = {2019},

date = {2019-01-01},

journal = {International Journal of Communication Systems},

volume = {32},

number = {15},

publisher = {John Wiley and Sons Ltd},

abstract = {In this work, we propose a highly efficient binary tree-based anti-collision algorithm for radio frequency identification (RFID) tag identification. The proposed binary splitting modified dynamic tree (BS-MDT) algorithm employs a binary splitting tree to achieve accurate tag estimation and a modified dynamic tree algorithm for rapid tag identification. We mathematically evaluate the performance of the BS-MDT algorithm in terms of the system efficiency and the time system efficiency based on the ISO/IEC 18000-6 Type B standard. The derived mathematical model is validated using computer simulations. Numerical results show that the proposed BS-MDT algorithm can provide the system efficiency of 46% and time system efficiency of 74%, outperforming all other well-performed algorithms. © 2019 John Wiley & Sons, Ltd.},

note = {cited By 1},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Saadi2019b,

title = {Visible light communication – An architectural perspective on the applications and data rate improvement strategies},

author = {M Saadi and T Ahmad and M Kamran Saleem and L Wuttisittikulkij},

url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-85061480801&doi=10.1002%2fett.3436&partnerID=40&md5=60473ad8fc5715cf2c6232115f948ba9},

doi = {10.1002/ett.3436},

issn = {21615748},

year  = {2019},

date = {2019-01-01},

journal = {Transactions on Emerging Telecommunications Technologies},

volume = {30},

number = {2},

publisher = {Wiley Blackwell},

abstract = {Demand for bandwidth hungry applications and mobile services is pushing an unquenchable need for wireless capacity. Existing radio frequency networks are characterized by shared medium, inadequate spectrum, and restricted user capacity. Solid state lighting is modernizing indoor as well as outdoor illumination. The capability of quick switching of light emitting diode makes them superior to other lighting sources enabling simultaneous use as a communication and illumination device. Visible light communication (VLC) using light emitting diodes is an attractive approach for many networking scenarios and is considered as a complementary technology for future heterogeneous wireless networks. This article presents an architectural perspective on the applications and data rate improvement strategies. A wide range of VLC applications have been investigated, comparison has been drawn with radio frequency, and generalized network architecture is also proposed. Numerous applications of VLC are data rate intensive, so data rate improvement approaches have also been studied. At the end, a lucid conclusion is drawn about the applicability, acceptability, and utilization of VLC and co-VLC–based systems. © 2018 John Wiley & Sons, Ltd.},

note = {cited By 14},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Saadi2019,

title = {Visible light-based indoor localization using k-means clustering and linear regression},

author = {M Saadi and Z Saeed and T Ahmad and M K Saleem and L Wuttisittikulkij},

url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-85052470702&doi=10.1002%2fett.3480&partnerID=40&md5=c442df6d8b92689ec8cef9f55df26953},

doi = {10.1002/ett.3480},

issn = {21615748},

year  = {2019},

date = {2019-01-01},

journal = {Transactions on Emerging Telecommunications Technologies},

volume = {30},

number = {2},

publisher = {Wiley Blackwell},

abstract = {Visible light positioning techniques employing received signal strength (RSS)–based fingerprints are becoming popular and ubiquitous. However, RSS is more susceptible to signal degradation and environmental changes resulting in location inaccuracies. To minimize these limitations, clustering in conjunction with linear regression is applied to RSS database made up of light intensity variations of light emitting diodes. Optimum cluster size is determined and trained clusters are exploited for location assessment by curtailing the difference between the database readings and cluster centroids. Regression is then applied on the clustered data, which partitions it further and helps refining the results. Simulation results of the proposed algorithm dictate a significant improvement in location estimation accuracy of up to 40 cm in an indoor environment with the dimensions of 5 m × 5 m × 4 m and exhibit superior performance than many state-of-the-art RSS-based methods. © 2018 John Wiley & Sons, Ltd.},

note = {cited By 7},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Wijayasekara2018,

title = {A collision resolution algorithm for RFID using modified dynamic tree with Bayesian tag estimation},

author = {S K Wijayasekara and S Nakpeerayuth and R Annur and W Srichavengsup and K Sandrasegaran and H -Y Hsieh and L Wuttisittikulkij},

url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-85051786638&doi=10.1109%2fLCOMM.2018.2865735&partnerID=40&md5=d1c40105566c26e2b30deac107bc165f},

doi = {10.1109/LCOMM.2018.2865735},

issn = {10897798},

year  = {2018},

date = {2018-01-01},

journal = {IEEE Communications Letters},

volume = {22},

number = {11},

pages = {2238-2241},

publisher = {Institute of Electrical and Electronics Engineers Inc.},

abstract = {A new tree-based anti-collision protocol for radio-frequency identification systems is proposed to achieve a very high tag identification efficiency. The proposed algorithm works in two phases. In the first phase, the number of competing tags is estimated through the proposed Bayesian estimation technique, while in the second phase, tags are identified using our modified dynamic tree algorithm. The system efficiency is mathematically derived and verified through simulation. Numerical results show that the proposed algorithm achieves a tag identification system efficiency of 45% and a time system efficiency of 78.5%, thus outperforming any existing collision resolution algorithms. © 1997-2012 IEEE.},

note = {cited By 10},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Prapasawasdi2018,

title = {Cultural tourism behaviors: Enhancing the influence of tourists’ perceptions on local thai food and culture},

author = {U Prapasawasdi and L Wuttisittikulkij and C Borompichaichartkul and L Changkaew and M Saadi},

url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-85056265888&doi=10.2174%2f1874350101811010184&partnerID=40&md5=0b94ad39327c034df02853987de8b70c},

doi = {10.2174/1874350101811010184},

issn = {18743501},

year  = {2018},

date = {2018-01-01},

journal = {Open Psychology Journal},

volume = {11},

number = {1},

pages = {184-197},

publisher = {Bentham Science Publishers B.V.},

abstract = {Background: Tourist behavior plays a principle role in preserving the cultural heritage and supporting the economy of the local community. Local food is a significant factor for tourists and an important cultural aspect distinguishing one country from one another. To understand tourists' food decision making, this study investigates tourists’ perceptions of local food. Methods: A mixed-method methodology used a concurrent transformative strategy. Qualitative research comprised in-depth interviews conducted with 15 local food specialists and 10 tourists; quantitative comprised survey structured questionnaires with a sample of 400 tourists travelling in Chiangmai, Thailand. Findings: The result revealed that tourists’ perceptions comprising attitude, subject norm, perceived value and expectation factors positively affected the perception toward local food information. Regression analysis suggested that the four variables contributed 53.4% to the variation of local food. By employing the standardized coefficients as mentioned, the linear regression model was Y = 0.424A-0.201S+0.428E+0.234P. Conclusion: Four factors affected tourists’ perceptions towards local food as follows: (1) expectation towards local food information via media, (2) attitude of tourists towards local food, (3) perceived value of local food with the benefit, belief and nutrition of local food, and (4) subject norm towards local food; local food experts influence to tourists. All the factors lead tourists to perceive in local food and culture. © 2018 Prapasawasdi et al.},

note = {cited By 1},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Wijayasekara2017,

title = {A reduced complexity of Vahedi’s tag estimation method for DFSA},

author = {S K Wijayasekara and A Robithoh and P Sasithong and P Vanichchanunt and S Nakpeerayuth and L Wuttisittikulkij},

url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-85033596884&doi=10.4186%2fej.2017.21.6.111&partnerID=40&md5=3e44bb78da08b391db8bfe196462c771},

doi = {10.4186/ej.2017.21.6.111},

issn = {01258281},

year  = {2017},

date = {2017-01-01},

journal = {Engineering Journal},

volume = {21},

number = {6 Special Issue},

pages = {111-125},

publisher = {Chulalongkorn University 1},

abstract = {In order to calculate the number of tags in a radio frequency identification (RFID) system, several tag estimation methods have been investigated in literature and most of the available estimation methods need the overall knowledge of idle, success and collision slots of the previous frame to carry out the tag estimation process. In this article, we present three techniques to reduce the complexity of Vahedi’s tag estimation for tag King Mongkut’s University of Technology North Bangkokcollision resolution in RFID systems using dynamic frame slotted ALOHA. Our modified and useful approach considers the information about only the number of empty, successful or colliding slots in the previous frame for the tag estimation. Three decision rules were obtained by maximizing the likelihood of success, idle and collision which helps in the reduction of complexity substantially. However, the accuracy of estimation decreases for success-only and idle-only methods while the collision-only method gives a consistent and lower estimate error when the frame sizes and the number of tags increase. © 2017, Chulalongkorn University 1. All Rights Reserved.},

note = {cited By 4},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Bajpai2016a,

title = {A New Construction Method for Large Girth Quasi-Cyclic LDPC Codes with Optimized Lower Bound using Chinese Remainder Theorem},

author = {A Bajpai and G Srirutchataboon and P Kovintavewat and L Wuttisittikulkij},

url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-84976401894&doi=10.1007%2fs11277-016-3465-8&partnerID=40&md5=5c9abaa4c41019c1fc113b59a7789323},

doi = {10.1007/s11277-016-3465-8},

issn = {09296212},

year  = {2016},

date = {2016-01-01},

journal = {Wireless Personal Communications},

volume = {91},

number = {1},

pages = {369-381},

publisher = {Springer New York LLC},

abstract = {This paper presents a new construction algorithm of Quasi-cyclic low-density parity-check (QC-LDPC) codes of medium to large block-length by combining QC-LDPC codes of small block-length as their component codes, via Chinese remainder theorem. Such component codes were constructed by permuting each column block sequentially to attain the desire local girth. After combining all component codes to generate an expanded parity-check matrix, the resulting girth is greater than or at least equal to the highest girth of component codes. We investigate a lower bound for circulant permutation matrices in the proposed method, which provides efficient and fast encoding for a desired girth, and has very simple structure and more economical in terms of hardware implementation. As already proven, a high girth parameter of the parity-check matrix ensures a good error correcting performance. Thus, simulation results show that our proposed construction method of the parity-check matrix significantly outperforms the other well-known existing methods, has low error-floor, and can reduce encoding complexity for medium to large block-length QC-LDPC codes. © 2016, Springer Science+Business Media New York.},

note = {cited By 8},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Saadi2014,

title = {Design and implementation of secure and reliable communication using optical wireless communication},

author = {M Saadi and A Bajpai and Y Zhao and P Sangwongngam and L Wuttisittikulkij},

url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-84922129671&doi=10.1515%2ffreq-2014-0027&partnerID=40&md5=a65b378b85a966f4d6719f8cacbec138},

doi = {10.1515/freq-2014-0027},

issn = {00161136},

year  = {2014},

date = {2014-01-01},

journal = {Frequenz},

volume = {68},

number = {11-12},

pages = {501-509},

publisher = {Walter de Gruyter GmbH},

abstract = {Wireless networking intensify the tractability in the home and office environment to connect the internet without wires but at the cost of risks associated with stealing the data or threat of loading malicious code with the intention of harming the network. In this paper, we proposed a novel method of establishing a secure and reliable communication link using optical wireless communication (OWC). For security, spatial diversity based transmission using two optical transmitters is used and the reliability in the link is achieved by a newly proposed method for the construction of structured parity check matrix for binary Low Density Parity Check (LDPC) codes. Experimental results show that a successful secure and reliable link between the transmitter and the receiver can be achieved by using the proposed novel technique. © 2015, Walter de Gruyter GmbH. All rights reserved.},

note = {cited By 14},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Wattanamongkhol2012,

title = {Analysis of effect of user misbehaviours on the reservation-based MAC protocols inwireless communication networks},

author = {N Wattanamongkhol and W Srichavengsup and P Vanichchanunt and R Annur and J -I Takada and L Wuttisittikulkij},

url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-84865687610&doi=10.1587%2ftranscom.E95.B.2794&partnerID=40&md5=b58450f5144678a276697123b242fc6c},

doi = {10.1587/transcom.E95.B.2794},

issn = {09168516},

year  = {2012},

date = {2012-01-01},

journal = {IEICE Transactions on Communications},

volume = {E95-B},

number = {9},

pages = {2794-2806},

publisher = {Institute of Electronics, Information and Communication, Engineers, IEICE},

abstract = {In a shared medium communication system, mobile users contend for channel access according to a given set of rules to avoid collisions and achieve efficient use of the medium. If one or more users do not comply with the agree rules either due to selfish or malicious behaviours, they will cause some impacts on the system performance, especially to the well-behaved users. In this paper, we consider the problem of user misbehaviours on the performance of a wireless infrastructure-based network using reservation-based MAC protocols. Key misbehaving strategies possible in such a network are identified and explained. To quantify the impact of these misbehaviours upon the network performance, three different misbehaving scenarios are developed to allow a systematic investigation of each misbehaving strategy. For each scenario, we have derived mathematical formulations for evaluating and analyzing the key performance metrics, i.e., probabilities of success of well-behaved and misbehaved users and the fairness index. Numerical results show that the presence of misbehaviours can cause different levels of damage depending on the misbehavior strategy used. The combined multi-token and increasing permission probability strategies where the misbehaved user selfishly accesses the channel more times and with higher probabilities than allowed is shown to cause the most severe impairment of performance and fairness. Copyright © 2012 The Institute of Electronics, Information and Communication Engineers.},

note = {cited By 0},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Woradit2009,

title = {Outage behavior of selective relaying schemes},

author = {K Woradit and T Q S Quek and W Suwansantisuk and M Z Win and L Wuttisittikulkij and H Wymeersch},

url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-73149110160&doi=10.1109%2fTWC.2009.080504&partnerID=40&md5=962c6eb0747f79176324589853a6b780},

doi = {10.1109/TWC.2009.080504},

issn = {15361276},

year  = {2009},

date = {2009-01-01},

journal = {IEEE Transactions on Wireless Communications},

volume = {8},

number = {8},

pages = {3890-3895},

abstract = {Cooperative diversity techniques can improve the transmission rate and reliability of wireless networks. For systems employing such diversity techniques in slow-fading channels, outage probability and outage capacity are important performance measures. Existing studies have derived approximate expressions for these performance measures in different scenarios. In this paper, we derive the exact expressions for outage probabilities and outage capacities of three proactive cooperative diversity schemes that select a best relay from a set of relays to forward the information. The derived expressions are valid for arbitrary network topology and operating signal-to-noise ratio, and serve as a useful tool for network design. © 2006 IEEE.},

note = {cited By 75},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Woradit2009a,

title = {Multicast routing and wavelength assignment with shared protection in multi-fiber WDM mesh networks: Optimal and heuristic solutions},

author = {K Woradit and M Guyot and P Vanichchanunt and P Saengudomlert and L Wuttisittikulkij},

url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-77956577614&doi=10.1587%2ftranscom.E92.B.3401&partnerID=40&md5=db8cafe5b0105349351941966b05880b},

doi = {10.1587/transcom.E92.B.3401},

issn = {09168516},

year  = {2009},

date = {2009-01-01},

journal = {IEICE Transactions on Communications},

volume = {E92-B},

number = {11},

pages = {3401-3409},

publisher = {Institute of Electronics, Information and Communication, Engineers, IEICE},

abstract = {While the problem of multicast routing and wavelength assignment (MC-RWA) in optical wavelength division multiplexing (WDM) networks has been investigated, relatively few researchers have considered network survivability for multicasting. This paper provides an optimization framework to solve the MC-RWA problem in a multi-fiber WDM network that can recover from a single-link failure with shared protection. Using the light-tree (LT) concept to support multicast sessions, we consider two protection strategies that try to reduce service disruptions after a link failure. The first strategy, called light-tree reconfiguration (LTR) protection, computes a new multicast LT for each session affected by the failure. The second strategy, called optical branch reconfiguration (OBR) protection, tries to restore a logical connection between two adjacent multicast members disconnected by the failure. To solve the MC-RWA problem optimally, we propose an integer linear programming (ILP) formulation that minimizes the total number of fibers required for both working and backup traffic. The ILP formulation takes into account joint routing of working and backup traffic, the wavelength continuity constraint, and the limited splitting degree of multicast-capable optical cross-connects (MC-OXCs). After showing some numerical results for optimal solutions, we propose heuristic algorithms that reduce the computational complexity and make the problem solvable for large networks. Numerical results suggest that the proposed heuristic yields efficient solutions compared to optimal solutions obtained from exact optimization. © 2009 The Institute of Electronics, Information and Communication Engineers.},

note = {cited By 0},

keywords = {},

pubstate = {published},

tppubtype = {article}

}