• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.15 no.3
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• pp.137-141
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• 2015

Mobile cloud computing uses cloud service to solve the resource constraint problem of mobile devices. Offloading means that a task executed on the mobile device commits to cloud and many studies related to the energy consumption have been researched. In this paper, we designed a response time model considering sensing data synchronization to estimate the efficiency of the offloading scheme in terms of the response time. The proposed model considers synchronization of required sensing data to improve the accuracy of response time estimation when cloud processes the task requested from a mobile device. We found that the response time is effected by new sensing data generation rate and synchronization period through simulation results.

• Journal of the Korean Electrochemical Society
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• v.10 no.4
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• pp.235-238
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• 2007

There is great interest in the applicability of generated hydrogen peroxide to a variety of industrial processes, usually involving oxidation of organics. Hydrogen peroxide is now employed for the bleaching as well as mechanical and chemical treatment in the pulp and paper industries. It addition, it is considered as an agent to displace the traditional alkaline treatments with chlorine-based chemicals. This paper reports a comparative study of $H_2O_2$ electogeneration on gas-diffusion electrode in divided cell with several $Nafion^{(R)}$ proton-exchange membranes, Russian cation-exchange membrane MK-40 and SPEEK membrane. The influence of different PEMs on electro-chemical cell voltage, current efficiency and energy consumption of hydrogen peroxide generation has been studied.

• Journal of information and communication convergence engineering
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• v.13 no.1
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• pp.21-26
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• 2015

A wireless sensor network (WSN) is designed and implemented for a freeze dryer. Freeze-drying technology is widely used in the fields of pharmacy and biotechnology as well as the food and agriculture industries. Taking into account the demand for high-resolution pressure and temperature measurements in a freeze dryer, the proposed WSN has a significant advantage of creating a monitoring environment in a freeze dryer. The proposed WSN uses a ZigBee/IEEE 802.15.4 network with an altimeter module that contains a high-resolution pressure and temperature sensor with a serial digital data interface. The ZigBee network is suitable for low-energy and low-data-rate applications in the field of wireless communication. The altimeter module is capable of sensing pressure in the range of 7.5-975 Torr (10-1300 mbar) and temperature in the range of $-40^{\circ}C$ to $125^{\circ}C$ with a DC power consumption of $3{\mu}W$. The implemented WSN is installed in a commercial laboratory freeze dryer in order to demonstrate its functionality and efficiency. A comparison with the temperature profile measured by a thermocouple installed in the freeze dryer reveals that the resolution of the temperature profile measured by WSN is superior to that measured by the thermocouple.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.35 no.9B
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• pp.1407-1415
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• 2010

In recent years, the smart grid technique for maximizing the energy efficiency of power networks has received a great deal of attentions. In particular, the Demand Response is a core technology differentiated from the present power network under the smart grid paradigm. To minimize the electric cost and maximize users' satisfaction, this paper proposes a unique scheduling algorithm derived by using optimization where the characteristics of various home appliances are taken into account. For this goal, we represent mathematical consumption patterns of the electric loads and propose the optimal scheduling scheme based on the importance factor of each device during one day. In the simulation results, we demonstrate the effectiveness of the proposed algorithm in the viewpoint of the minimal electric costs utilizing real statistical figures.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.33 no.3B
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• pp.123-134
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• 2008

In this paper, a routing algorithm for wireless sensor networks is proposed to improve the efficiency of energy consumption in sensor nodes. Each sensor node has the value called ‘Flooding Level’ obtained through the initial flooding from a sink node instead of sending beacon messages in multi-hop sensor field. This value can be used for guaranteeing the sensor nodes to connect with a sink node and determining the roles of cluster-head and cluster-gateway node efficiently and simply during the clustering. If different algorithms are added to our protocol, it will work better in the side of energyefficiency. This algorithm is evaluated through analysis and extensive simulations.

• Membrane and Water Treatment
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• v.3 no.1
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• pp.63-76
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• 2012

Mother liquid discharged from a salt-manufacturing plant was electrodialyzed at 25 and $40^{\circ}C$ in a continuous process integrated with $SO_4{^{2-}}$ ion low-permeable anion-exchange membranes to remove $Na_2SO_4$ and recover NaCl in the mother liquid. Performance of electrodialysis was evaluated by measuring ion concentration in a concentrated solution, permselectivity coefficient of $SO_4{^{2-}}$ ions against $Cl^-$ ions, current efficiency, cell voltage, energy consumption to obtain one ton of NaCl and membrane pair characteristics. The permselectivity coefficient of $SO_4{^{2-}}$ ions against $Cl^-$ ions was low enough particularly at $40^{\circ}C$ and $SO_4{^{2-}}$ transport across anion-exchange membranes was prevented successfully. Applying the overall mass transport equation, $Cl^-$ ion and $SO_4{^{2-}}$ ion transport across anion-exchange membranes is evaluated. $SO_4{^{2-}}$ ion transport number is decreased due to the decrease of electro-migration of $SO_4{^{2-}}$ ions across the anion-exchange membranes. $SO_4{^{2-}}$ ion concentration in desalting cells becomes higher than that in concentration cells and $SO_4{^{2-}}$ ion diffusion is accelerated across the anion-exchange membranes from desalting cells toward concentrating cells.

• The Korean Journal of Zoology
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• v.34 no.4
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• pp.594-609
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• 1991

연안 천해에 서식하는 반부유성 갑각류인 감eomysis awatschensis를 수온 16$^{\circ}C$와 $25^{\circ}C$에서 Anemiusalina유생을 먹이로 공급하며 사육하면서 성장과 탈피에 미치는 수온의 영향을 조사, 성장, 탈피, 생식 및 호흡에 쓰인 에너지량과 체를필의 화학적 조성 및 에너지 함량을 측정한 자료로부터 개체의 사용 에너지 수지를 계산하였다. N. awatschensis 자웅의 총평균 체장성장율은 16$^{\circ}C$에서 0.08 mm/day, $25^{\circ}C$에서는 0.12maydaY였다. 수온은 동물의 각 탈피간 체장증가 백분율(growth factor)에는 영향을 미치지 않았으나 탈피기간에는 뚜렷한 영향을 나타내었다. 암컷의 체장별 각 탈피간 체장증가율은 수컷에 비하여 평균 3oye 정도 높았다. 성장과 탈피에 사용하는 평균 에너지는 각각 5.55 cal/mg X (건중, mg) 및 0.337 col/mg X (건중, mg)이였다. 난 1개의 에너지 함량은 0,057 cal이고, 암컷이 생식에 사용하는 에너지는 체장별 포란수와 관련되었다. 호흡계수는 4.5 col/ml 02였고, 회분비방법에 의한 동화효율은 70.9%였다. N. owotschensis의 총사용 에너지 중 성장에 사용하는 에너지는 갑각류의 다른 종에 비하여 높았다.

• Journal of the Institute of Electronics Engineers of Korea SD
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• v.38 no.4
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• pp.285-291
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• 2001

An 8-b$\times$8-b adiabatic pipelined multiplier is designed. Simplified four phase clock generator is also designed to provide supply clocks for adiabatic circuits. All the clock line charge on the capacitive interconnections is recovered to save energy. Adiabatic circuits are designed based on ECRL(efficient charge recovery logic) and are integrated using 0.6${\mu}{\textrm}{m}$ CMOS technology. The efficiency of proposed supply clock generator is better than the previous one by 4~11%. Simulation results show that the power consumption of adiabatic pipelined multiplier is reduced by a factor of 2.6~3.5 compared to a conventional pipelined CMOS multiplier.

• Structural Engineering and Mechanics
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• v.39 no.1
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• pp.147-168
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• 2011

To ensure safety and long term performance, structural control has rapidly matured over the past decade into a viable means of limiting structural responses to strong winds and earthquakes. Nonlinear response history analysis requires rigorous procedure to compute seismic demands. Therefore the simplified nonlinear analysis procedures are useful to determine performance of the structure. In this investigation, application of improved capacity demand diagram method in the control of structural system is presented for the first time. Developed pole assignment method (DPAM) in structural systems control is introduced. Genetic algorithm (GA) is employed as an optimization tool for minimizing a target function that defines values of coefficient matrices providing the placement of actuators and optimal control forces. The ground acceleration is modified under induced control forces. Due to this, performance of structure based on improved nonlinear demand diagram is selected to threshold of nonlinear behavior of structure. With small energy consumption characteristics, semi-active devices are especially attractive solutions for limiting earthquake effects. To illustrate the efficiency of DPAM, a 30-story steel moment frame structure employing the semi-active control devices is applied. In comparison to the widely used linear quadratic regulation (LQR), the DPAM controller was shown to be just as effective and better in the reduction of structural responses during large earthquakes.

• International Journal of Naval Architecture and Ocean Engineering
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• v.6 no.3
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• pp.715-722
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• 2014

Three twisted rudders fit for large container ships have been developed; 1) the Z-twisted rudder that is an asymmetry type taking into consideration incoming flow angles of the propeller slipstream, 2) the ZB-twisted rudder with a rudder bulb added onto the Z-twisted rudder, and 3) the ZB-F twisted rudder with a rudder fin attached to the ZB-twisted rudder. The twisted rudders have been designed computationally with the hydrodynamic characteristics in a self-propulsion condition in mind. The governing equation is the Navier-Stokes equations in an unsteady turbulent flow. The turbulence model applied is the Reynolds stress. The calculation was carried out in towing and self-propulsion conditions. The sliding mesh technique was employed to simulate the flow around the propeller. The speed performances of the ship with the twisted rudders were verified through model tests in a towing tank. The twisted versions showed greater performance driven by increased hull efficiency from less thrust deduction fraction and more effective wake fraction and decreased propeller rotating speed.