• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.16 no.1
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• pp.147-153
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• 2016

Recently, IETF (Internet Engineering Task) working group has adopted CoAP (Constrained Application Protocol) as a standard IoT proctocol. CoAP is a specialized web transfer protocol for use with constrained nodes and constrained environment such as small memory and low power networks. In this paper, we design and implement a registration service with CoAP protocol based on RD(Resource Directory) to connect IoT nodes in mobile Internet environments. The resource directory between the mobile terminal and IoT nodes provides to discover the IoT nodes and get the context data. The mobile terminal has as the CoAP client and embedded IoT nodes includes as the CoAP server so that it can conveniently manage the constrained IoT nodes to get the context data and control devices in a mobile environments.

• Journal of Internet Computing and Services
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• v.9 no.2
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• pp.43-50
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• 2008

In IEEE 802.11b wireless LAN, stations keep synchronization by receiving beacons being periodically sent by the AP (access point) when they run in low power mode. Beacon transmission is delayed if wireless channel is busy at a scheduled TBTT (target beacon transmission time), and stations must be awake until they receive the delayed beacon. In this paper, we propose a scheme that stations get their transmission delayed if they have little time for successful data transmission by the next TBTT. Beacon transmission without delay is guaranteed at every TBTT with this method so that the awake time of low power stations to receive beacon can be reduced. The proposed method is simulated and its characteristics ore described with the analysis of the results. The measured results in terms of beacon delay show some enhancement in energy consumption.

• Nuclear Engineering and Technology
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• v.30 no.4
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• pp.342-352
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• 1998

A nuclear design feasibility of soluble boron free(SBF core for the medium-sized(600MWe) PWR was investigated. The result conformed that soluble boron free operation could be performed by using current PWR proven technologies. Westinghouse advanced reactor, AP-600 was chosen as a design prototype. Design modification was applied for the assembly design with burnable poison and control rod absorber material. In order to control excess reactivity, large amount of gadolinia integral burnable poison rods were used and B4C was used as a control rod absorber material. For control of bottom shift axial power shape due to high temperature feedback in SBF core, axial zoning of burnable poison was applied to the fuel assemblies design. The combination of enrichment and rod number zoning for burnable poison could make an excess reactivity swing flat within around 1% and these also led effective control on axial power offset and peak pin power, The safety assessment of the designed core was peformed by the calculation of MTC, FTC and shutdown margin. MTC in designed SBF core was greater around 6 times than one of Ulchin unit 3&4. Utilization of enriched BIO(up to 50w1o) in B4C shutdown control rods provided enough shutdown margin as well as subcriticality at cold refueling condition.

• Nuclear Engineering and Technology
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• v.56 no.7
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• pp.2595-2609
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• 2024

This paper introduces a base isolation system-tuned mass damper inerter (BIS-TMDI) hybrid system to the AP1000 nuclear power plant (NPP), which reduces seismic damage potential of the NPP structure. The effects of fluid-structure interaction (FSI) caused by the passive containment cooling system water storage tank (PCCWST) on NPP's seismic performance are investigated. The FSI of water tank theoretical model is considered based on the Housner's model, and a series of time history analyses are performed to prove the rationality of the proposed model. Three single-objective optimization strategies are employed to minimize the relative displacement variance and absolute acceleration variance of the upper structure, as well as the filtered energy index (FEI). Furthermore, a multi-objective optimization strategy considering all these three indexes is proposed to obtain optimal parameters of vibration control. The influence of vibration control strategies on the relative deformation and acceleration of the upper structure is explored with various water level ratios. The analytical results indicate that the proposed BIS-TMDI strategy has significantly reduced the NPP structure's seismic response. The effectiveness of the vibration control strategy is influenced by the water level ratio, emphasizing the significance of designing an appropriate water level ratio to reduce NPP structure's seismic response.

• Journal of Satellite, Information and Communications
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• v.12 no.2
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• pp.51-55
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• 2017

This paper aims to maximize the energy harvesting rate and channel capacity in RF-energy harvesting networks (RF-EHNs) under the constraints of maximum transmit power and minimum quality of service (QoS) in terms of rate capacity for each user. We study a multi-user RF-EHN with frequency division multiple access (FDMA) in a Rayleigh channel. An access point (AP) simultaneously transmitting wireless information and power in the RF-EHN serves a subset of active users which have a power-splitting antenna. To gauge the network performance, we define energy efficiency (EE) and propose an optimization solution for maximizing EE with Lagrangian dual decomposition theory. In simulation results, we confirm that the EE is effectively maximized by the proposed solution with satisfying the given constraints.

• Proceedings of the KIEE Conference
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• 2001.07b
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• pp.647-649
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• 2001

It is a indispensible condition that the simulation and the experiment to improve a efficiency of maglev system. We usually carry out the simulation using the approximate equation, because it is impossible to use a exact modeling such as a practice modeling. This paper proposed a ideal simulation ap to the maglev system modeling by Finite Ele Method. To save the electrical energy, zero p control method is used, and verifying the feasibi FEM dynamic simulation, we make an exper with a TI DSP TMS320F240-based hardware.

• Journal of Acupuncture Research
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• v.33 no.3
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• pp.45-66
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• 2016

Objectives : The purpose of this study is to find parameters to compare the effects of Sa-Am acupuncture with gall bladder jeonggyeok and seunggyeok on radial pulse in healthy subjects. Methods : 60 healthy subjects participated in this study and divided into the gall bladder jeonggyeok group (GB+ group), the gall bladder seunggyeok group (GB- group) and the control group. Radial pulse was measured by a 3 dimensional pulse imaging system (DMP-3000) before, immediately after, 30 minutes after and 60 minutes after acupuncture on the Cun, Guan and Chi in the GB+, GB- group and at the same time for the control group. Results : 1. The GB+ and GB- group exhibited significantly increased T, M4/M1 and decreased T1/T, T2/T, T5/T, M1, M2 compared to the control group. 2. The GB+ and GB- group exhibited significantly increased H4, Ad/Ap, RAI/HR and decreased As/Ap, Aw/Ap in the right Guan and decreased pulse power volume/min in the left Guan compared to the control group. 3. The GB- group exhibited significantly decreased M3, M3/M1 and increased M4/M1, M5, M5/M1 compared to the GB+ group. The GB+ group exhibited significantly decreased T4/(T-T4) compared to the GB- group. 4. The GB- group exhibited significantly decreased H1 in the right Guan, Chi, H4, pulse area in the right Chi, H5, pulse power volume/min in the left Chi, right Chi, and increased main peak angle in the right Guan, Chi compared to the GB+ group. Conclusion : The effect of gall bladder jeonggyeok and seunggyeok in healthy humans may be observed on various parameters. The parameters analyzed in this study may be used to differentiate effects between gall bladder jeonggyeok and seunggyeok on radial pulse. Further studies on the effects of Sa-Am acupuncture using radial pulse are needed.

• International Journal of Internet, Broadcasting and Communication
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• v.10 no.3
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• pp.35-41
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• 2018

Smart device has become an affordable main computing resource for robotic ap-plications in accordance with a fast growth of mobile internet environment. Since the computing power of smart device has been increased, smart device based ro-bot system attempts to replace traditional robot applications with laptop-based system. Methodologies for acquisition of remote sensory information and control of various types of robots using smart device have been proposed recently. In this paper, we propose a robot control system using a monitoring program and a communication protocol. The proposed system is a combination of an educa-tional programming oriented robot named EPOR-S. as small service robot plat-form and a smart device. Through a simulation study using image processing, the feasibility of combination of the proposed robot monitoring program and control system was verified.

• Nuclear Engineering and Technology
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• v.27 no.3
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• pp.336-343
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• 1995

The Self Tuning Regulator(STR) method which is an approach of adaptive control theory, is ap-plied to design the fully automatic power controller of the nonlinear reactor model. The adaptive control represent a proper approach to design the suboptimal controller for nonlinear, time-varying stochastic systems. The control system is based on a third­order linear model with unknown, time-varying parameters. The updating of the parameter estimates is achieved by the recursive extended least square method with a variable forgetting factor. Based on the estimated parameters, the output (average coolant temperature) is predicted one-step ahead. And then, a weighted one-step ahead controller is designed so that the difference between the output and the desired output is minimized and the variation of the control rod position is small. Also, an integral action is added in order to remove the steady­state error. A nonlinear M plant model was used to simulate the proposed controller of reactor power which covers a wide operating range. From the simulation result, the performances of this controller for ramp input (increase or decrease) are proved to be successful. However, for step input this controller leaves something to be desired.

• Proceedings of the KIPE Conference
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• 2003.07a
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• pp.243-246
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• 2003

This paper presents a new motor design well suited for an advanced exercise bike. The advanced exercise bike setup high demands for performance and physical dimensions, which is high torque, wide speed range and a diameter/length ratio around 5. These requirements makes the new motor design called an E-core Transverse Flu Machine (ETFM) vev interesting because the segmented design of the stator and rotor poles enables high diameter without increasing the flux-path and since the ETFM is similar to the switched reluctance motor, high torque and wide speed range is possible. The design of the ETFM can be peformed using a developed design program, which is also introduced in the paper. A prototype of the exercise bike with the ETFM and a classical H-bridge converter with analog current control is constructed for verification of the concept.