Browsing by Author "Tsai, I-Hsin"

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Minimizing electromagnetic pollution and power consumption in green heterogeneous small cell network deployment
(2017-12-24)
Lin, Chun-Cheng
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Tsai, Ching-Tsorng
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Deng, Der-Jiunn
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Tsai, I-Hsin
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Jhong, Shun-Yu
An enormously increasing number of mobile communications devices and IoT sensors have driven rapid advance in wireless and cellular network technologies. Owing to limited energy resources, 5G technology has been expected to be designed as a 'green' network system. To achieve the requirement of future 'green' 5G networks to serve a huge number of mobile devices, this work investigates the problem of deployment and sleep control of a 'green' heterogeneous cellular network along a highway composed of base stations (BSs), legacy relay stations (RSs), and small cells (SCs), with two objectives: minimizing the energy consumption to decrease the impact of limited energy; as well as minimizing the electromagnet pollution from radiation of the three device types to avoid the potential harm to creatures. For decision variables, the deployment and sleep control of legacy RSs and SCs affect the total power consumption, and their coverage affects the total electromagnet pollution. First, this work creates a mathematical model for the optimization problem, and then proposes a hybrid algorithm of genetic algorithm (GA) and differential evolution (DE) with three local search operators to solve the problem, in which GA and DE can effectively handle discrete and continues decision variables, respectively. Simulation of the concerned green cellular networks verifies performance of the proposed algorithm. (C) 2017 Elsevier B.V. All rights reserved.
On Lifetime Enhancement of Dynamic Wireless Sensor Networks with Energy-Harvesting Sensors
(2016)
Lin, Chun-Cheng
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Deng, Der-Jiunn
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Shu, Lei
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Wang, Kun
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Wang, Shang-Bin
This work investigates the problem of extending the lifetime of dynamic WSNs with energy-harvesting (EH) sensors to enhancing the total WSN lifetime. This problem is modeled as finding the maximal number of covers each of which can cover all targets to be monitored. Since the concerned problem is also NP-complete, this work proposes a novel harmony search algorithm. By simulation, the proposed algorithm is shown to be promising.
Resource allocation of simultaneous wireless information and power transmission of multi-beam solar power satellites in space-terrestrial integrated networks for 6G wireless systems
(1970-01-01)
Lin, Chun-Cheng
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Su, Nai-Wei
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Deng, Der-Jiunn
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Tsai, I-Hsin
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工業工程與管理學系
The technique of simultaneous wireless information and power transmission (SWIPT) has been applied to wireless sensor networks, which employ static or mobile base stations (BSs) such as drones and ships to charge passively powered devices. SWIPT can be strongly expanded by solar power satellites (SPSs), which collect solar energy and transmit it to the earth through microwaves to alleviate the power shortage problem. Furthermore, multi-beam SPSs can serve a broader range than terrestrial BSs for information transmission.In 6G networks, satellites are core devices in space-terrestrial integrated networks (STINs) supporting super Internet-of-Things. However, when discussing 6G wireless systems, previous works did not consider SWIPT applied in STINs through multi-beam SPSs. Therefore, this work proposes a novel resource allocation problem for SWIPT performed by multi-beam SPSs in the STIN while optimizing the following two objectives: minimizing deficit or excess of information transmission rate and maximizing power transmission based on two receiving architectures of terrestrial devices for information decoding and energy harvesting. Different from previous works, this problem considers not only assigning power to one of multiple satellite beams but also further allocating power in each beam into two parts for information and power transmission. This problem is NP-hard as it includes an NP-hard problem. Artificial intelligence (AI) algorithms can be used to optimize the network resource management. Hence, this problem with continuous decision variables is further solved by a classical and two recent AI algorithms specially designed for continuous variables, i.e., particle swarm optimization, improved harmony search algorithm, and monkey algorithm. Through simulation, the most appropriate AI algorithms to the concerned problem are analyzed, and the results show that for the two special designed receiving architectures of the terrestrial devices, the power splitting architecture generally outperforms the time switching architecture.
Solution processable bilayered gate dielectric towards flexible organic thin film transistors
(2015-04-01)
Singh, Ranjodh
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Meena, Jagan Singh
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Tsai, I-Hsin
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Lin, Yen-Ting
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Wang, Cheng-Jyun
In this study, we have successfully explored the potential of a new bilayer gate dielectric material, composed of Polystyrene (PS), Pluronic P123 Block Copolymer Surfactant (P123) composite thin film and Polyacrylonitrile (PAN) through fabrication of metal insulator metal (MIM) capacitor devices and organic thin film transistors (OTFTs). The conditions for fabrication of PAN and PS-P123 as a bilayer dielectric material are optimized before employing it further as a gate dielectric in OTFTs. Simple solution processable techniques are applied to deposit PAN and PS-P123 as a bilayer dielectric layer on Polyimide (PI) substrates. Contact angle study is further performed to explore the surface property of this bilayer polymer gate dielectric material. This new bilayer dielectric having a k value of 3.7 intermediate to that of PS-P123 composite thin film dielectric (k similar to 2.8) and PAN dielectric (k similar to 5.5) has successfully acted as a buffer layer by preventing the direct contact between the organic semiconducting layer and high k PAN dielectric. The OTFT devices based on alpha,omega-dihexylquaterthiophene (DH4T) incorporated with this bilayer dielectric, has demonstrated a hole mobility of 1.37 x 10(-2) and on/off current ratio of 10(3) which is one of the good values as reported before. Several bending conditions are applied, to explore the charge carrier hopping mechanism involved in deterioration of electrical properties of these OTFTs. Additionally, the electrical performance of OTFTs, which are exposed to open atmosphere for five days, can be interestingly recovered by means of re-baking them respectively at 90 degrees C. (C) 2015 Elsevier B.V. All rights reserved.