• 한국통신학회논문지
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• 제41권5호
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• pp.539-545
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• 2016

이 논문에서는 단말 간 직접 통신(Device-to-Device: D2D) 링크가 있는 셀룰러 망 안에서 증폭 후 전달 (Amplify-and- Forward: AF) 방식의 조력국을 사용하여 D2D 전송률을 높이고 D2D 단말기가 셀룰러 망에 미치는 간섭을 제어하는 방법을 제안한다. 전체 시스템의 quality-of-service (QoS)를 높이기 위해 두 가지 방법으로 조력국을 설계한다. 첫 번째는 D2D 단말기가 셀룰러 망에 미치는 간섭을 제한하면서 최저 D2D 전송률을 최대화하는 문제이고, 두 번째는 이것의 dual 문제인 각 D2D 단말기의 최소 전송률을 보장하면서 D2D 단말기가 셀룰러망에 미치는 간섭을 최소화하는 문제이다. 또한, 이 문제들은 semi-definite programming (SDP) 문제로 바뀔 수 있음을 보인다. 실험 결과에서는 AF 조력국이 시스템의 성능을 획기적으로 향상시킬 수 있음을 보인다.

• 상하수도학회지
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• 제24권4호
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• pp.377-386
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• 2010

To identify operating parameters of the up-flow filtering system, which is available to discharge filtering residue after the rain, developed for treatment of urban storm runoff, lab scale test was carried out. Removal efficiency of SS was 68.7%, 62.2%, and 58.6% at the area roading rate of 2.46m/h, 4.68m/h, and 10m/h, respectively, filtering device is desirable to operate at the lower than 4.68m/h of area roading rate to get higher level of 60% SS removal efficiency. The removal efficiency of SS was 57.1% ~ 68.7% at the raw water SS of 100mg/L ~ 600mg/L, and the SS in treated water was maintained at the constant level through the elapsed time. It is indicate that filtering device can guarantee a certain level of effluent water quality at various raw water quality. The removal efficiency of SS to the depth of filter media was 68.3%, 78.6% at the filter depth of 10 cm, 20cm respectively. The final treated water quality was showed 30.2mg/L of CODMn, 1.60mg/L of TN and 0.25mg/L of TP. The average removal efficiencies by filtering device developed in this research were recorded slightly lower levels than other research. The main reason of these results were the first, the filter depth of the media used in this test was shallow, the second, the kind of filter media in discharge port of residue. More research to kind of filter media, filter packing rate, select of media for residue discharge port should be go on to produce optimum operating condition. The result of this study would be valuable for the application of filtration device to control of urban storm water.

• 대한방사선기술학회지:방사선기술과학
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• 제39권4호
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• pp.527-534
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• 2016

DEXA는 골다공증 진단에 가장 많이 사용되는 표준 측정법이다. 현재 국내에서 운영되고 있는 DEXA 장치는 5,671대이다. 본 연구에서는 국내에서 설치 운영되고 있는 DEXA장비의 품질관리 실태를 조사하였다. 3,000개 기관을 대상으로 한 설문 조사에서 12.6%의 응답을 받아 그 결과를 분석하였다. 결과에서 77.5%가 일일 품질관리를 시행하고 있으나 Shewhart chart는 68.5%, CUSUM chart는 86.0%가 모르거나 사용하지 않는다고 답하여 정확한 품질관리가 되지 않는 것으로 조사되었다. 정확한 골밀도 검사는 환자의 골절의 위험도를 산정하기 위한 자료로 활용된다. 하지만 부적절한 검사는 오진을 유발할 가능성을 높여준다. 따라서 정확한 골밀도 검사를 위해서는 적절한 보조기구를 사용하고 장치의 품질관리를 반드시 시행하여 장치와 자세에 대한 오차를 줄이고 검사 의료진의 교육을 통해 오류 요인을 줄이는 것이 필수적이다.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2000년도 추계학술대회 논문집
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• pp.393-396
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• 2000

Spent fuel rod cutting device should cut a spent fuel rod to an optimal size in order to fast decladding operation. In this paper, for developing spent fuel rod cutting device with cutter blade, rod properties such as dimension and material of zircaloy tube and fuel pellet are investigated at first and then, various methods of existing cutting devices used commercially are investigated and their performance are analyzed and compared. This device is designed to be operated automatically via remote control system considering later use in Hot-Cell (radioactive area) and the mdularization in the structure of this device makes maintenance easy. SUS and Zircaloy-4 are selected as cut material used in the test of spent fuel rod cutting device by cutter blade. In order for constructing the high durable cutter blade, various materials are analyzed in terms of quality, shape, characteristic, and heat treatment, etc. and from these results, spent fuel rod cutting device is designed and manufactured based on the considerations of durability, round shape sustainability of rod cross-section, debris generation, and fire risk, etc.

• 산업안전기술지
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• 제2권1호
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• pp.6-10
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• 2002

Requirements for Distributed Monitoring and Control Networks(DMCN) differ greatly from those of typical data networks. Specifically, my DMCN technology which employs a filedbus protocol is different from IP network protocol TCP/IP. In general, one needs to integrate fieldbus protocol and TCP/IP to realize DMCN over IP network or internet, which can be viewed as Virtual Device Network(VDN). Interoperability between devices and equipments is essential to enhance the quality and the performance of predictive maintenance(PM). This paper suggests a basic framework for VDN using DMCN over IP network and a method to guarantee interoperability between devices and equipments.

• 대한의용생체공학회:의공학회지
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• 제41권6호
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• pp.256-263
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• 2020

The importance of quality control has been emphasized to maintain safety of patients and satisfaction of medical service with medical devices used in clinic. Accordingly, objective evaluation method and standards consistently has been brought up for demand to replace outdated medical devices in appropriate time and to maintain the quality of medical service. Though many studies made suggestions methods to determine what medical devices to be replaced first, these methods were difficult in practice for its complex evaluation criteria and long time to evaluate. Therefore, in this study, a simple evaluation method is developed to identify and prioritize medical devices that are ought to be replaced. For the development of this simple evaluation method, four major characteristics of technology, safety, finance, and user satisfaction, which are considered in clinics to evaluate medical device replacement, and 14 minor attributes are distinctively selected. Each characteristic is assessed in binary form of "YES" or "NO" to minimize its subjective nature. Using this method to evaluate sampled medical devices belonging to four different characteristics, devices are suggested to be replaced in the current financial year or in the following financial year, or re-evaluated by the end of this financial year. Such results of evaluation can amend the subjective nature of existing evaluation method and give objective standards more promptly.

• 한국전기전자재료학회논문지
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• 제24권1호
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• pp.36-41
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• 2011

Medical X-ray has been brought many changes according to the rapid development of high technology. Especially, for high-voltage generator which is the most important in X-ray generation the traditional way is to use high-voltage electric transformers primarily. However, since it is large and heavy and the ripple rate of DC high-voltage applied to X-ray tube is too big, it has a disadvantage of low X-ray production efficiency. To solve these problems, the studies about high-voltage power supply are now proceeding. At present, the high-voltage generator that generates high-voltage by making high frequency using inverter control circuit consisting of semiconductor device is mainly used. High-voltage generator using inverter has advantages in the diagnosis using X-ray including high performance with short-term use, miniaturization of power supply and ripple reduction. In this study, the X-ray high-voltage device with inverter type using pulse width modulation scheme to the control of tube voltage and tube current was designed and produced. For performance evaluation of produced device, the control signal analysis, irradiation dose change and beam quality depending on the load variation of tube voltage and tube current were evaluated.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제15권7호
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• pp.2631-2649
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• 2021

Device-to-Device (D2D) communication is one of the enabling technologies for 5G networks that support proximity-based service (ProSe) for wireless network communications. This paper proposes a power control algorithm based on the Nash equilibrium and game theory to eliminate the interference between the cellular user device and D2D links. This leadsto reliable connectivity with minimal power consumption in wireless communication. The power control in D2D is modeled as a non-cooperative game. Each device is allowed to independently select and transmit its power to maximize (or minimize) user utility. The aim is to guide user devices to converge with the Nash equilibrium by establishing connectivity with network resources. The proposed algorithm with pricing factors is used for power consumption and reduces overall interference of D2Ds communication. The proposed algorithm is evaluated in terms of the energy efficiency of the average power consumption, the number of D2D communication, and the number of iterations. Besides, the algorithm has a relatively fast convergence with the Nash Equilibrium rate. It guarantees that the user devices can achieve their required Quality of Service (QoS) by adjusting the residual cost coefficient and residual energy factor. Simulation results show that the power control shows a significant reduction in power consumption that has been achieved by approximately 20% compared with algorithms in [11].

• 전기학회논문지P
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• 제56권1호
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• pp.13-18
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• 2007

In this paper, authors deal with an application of power quality monitoring using the Sampled Value which is described in the IEC61850 International Standard for substation communication. Firstly, while Merging Unit is designed as a process level device transmitting sensor data, the practical problems such as time delay compensation and optical fiber communication are issued. Secondly, the Sampled Value message which is proper to a power quality monitoring system is presented. Because the power quality monitoring system requests non time critical service comparing to protection and control applications, the Sampled Value service message structure is introduced to improve efficiency. At last, the power quality monitoring server having various power quality analysis functions is suggested to verify the performance of Merging Unit. With the diverse experiments, it is proved that the process bus distributed solution is flexible and economic for the power quality monitoring.

• JSTS:Journal of Semiconductor Technology and Science
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• 제14권2호
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• pp.169-174
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• 2014

As a versatile processing method for nanoscale memory integration, laser-induced epitaxial growth is proposed for the fabrication of vertical Si channel (VSC) transistor. The fabricated VSC transistor with 80 nm gate length and 130 nm pillar diameter exhibited field effect mobility of $300cm^2/Vs$, which guarantees "device quality". In addition, we have shown that this VSC transistor provides memory operations with a memory window of 700 mV, and moreover, the memory window further increases by employing charge trap dielectrics in our VSC transistor. Our proposed processing method and device structure would provide a promising route for the further scaling of state-of-the-art memory technology.