• Journal of information and communication convergence engineering
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• 제16권1호
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• pp.23-30
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• 2018

In cognitive radio (CR), spectrum sensing is an essential function since secondary users (SUs) must determine whether the primary user (PU) is utilizing the channel or not, and furthermore, SUs opportunistically access the licensed channel when the PU is absent. In this paper, spectrum sensing is implemented by energy detection, and a software-defined radio testbed is built to evaluate sensing performance by energy detection in a real environment. In particular, the testbed was built based on the GNU's Not Unix (GNU) Radio software platform and Universal Software Radio Peripheral National Instruments 2900 devices. More specifically, a new block of energy detection is developed by using an out-of-tree module from GNU Radio. To successfully integrate CR into the cloud computing paradigm, we also implement cloud computing-based spectrum sensing by utilizing a cloud server with ThingSpeak, such that we can store, process, and share the sensing information more efficiently in a centralized way in the cloud server.

• 한국주거학회논문집
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• 제23권5호
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• pp.41-49
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• 2012

As improving our standard of living, demographic change or industrial development, MSW that is closely linked to human behavior has been occurred much change. Notably, we usually have incinerated the combustible waste. In the process, they also emit a large amount of greenhouse gas that has directly affected the global warming and environmental pollution. Therefore, we need to make control system to manage future production and reduce generation of MSW. Thus this study analyzed the generation of MSW according to household members and floor area in apartment housing occupies the highest share. Then, we used both a correlation analysis and a regression analysis to make new estimation model of MSW generation. Based on this study, the results were used to suggest a method to efficiently handle MSW in the case of planning urban environment. Also, build a database to set up the integrated management system of MSW in the future.

• 가정과삶의질연구
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• 제23권6호
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• pp.1-13
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• 2005

The aim of this study is to investigate the housework space viewed from housewives and husband in dual-earner families. For this study, depth-interview method were used to collects the data. The depth-interview were conducted on the eight heusewives and two husbands in dual-earner families in Jinju and Gwangju in April 2005. The narratives were then analyzed to discover the demands of the kitchen and laundry room. The major results were as follows: 1) Dual-earner families want the kitchen design is they can share housework with their spouses, such as kitchen facing the front side of the floor plan and island counter. In addition, they want spacious, adjustable(flexible), visible storage to enable the housewives to work with their spouse efficiently. Space for Kimchi refrigerator should be considered in the kitchen. 2) They want the noise-free laundry because the interviewers did their laundry work in the night time. Also, they want a multi-purpose laundry mm where machine washing, hand washing, drying and ironing can be done. In addition, for hand-washing wives and husbands, specific space and facilities where they can hand washing on stand posture were needed.

• 대한전기학회논문지:전력기술부문A
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• 제48권6호
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• pp.760-772
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• 1999

The CAN is a serial communication protocol for distributed real-time control and automation systems. Data generated from field devices in the distributed control of power plant are classified into three categories: real-time event data, real-time control data, non-real-time data. These data share a CAN medium. If the traffic of the CAN protocol is not efficiently controlled, performance requirements of the power plant system could not be satisfied. This paper proposes a bandwidth allocation algorithm that can be applicable to the CAN protocol. The bandwidth allocation algorithm not only satisfies the performance requirements of the real-time systems in the power plant but also fully utilizes the bandwidth of CAN. The bandwidth allocation algorithm introduced in this paper is validated using the integrated discrete-event/continuous-time simulation model which comprises the CAN network and distributed control system of power plant.

• Journal of Advanced Marine Engineering and Technology
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• 제16권4호
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• pp.102-112
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• 1992

The three-phase full(6-pulse) bridge controlled rectifier is one of the most widely used types of solid-state converters in DC drive applications for higher performance. In most of the previous designs, the gate control circuits of the converter have been designed with analog method which can be easily affected by noise. Nowdays with advances of microelectronics and power electronics, microprocessor and pheripal LSIs are increasingly used for eliminating this problems. In this paper, a novel general-purpose microprocessor -based firing system and control scheme for a three-phase controlled rectifier bridge has been developed and tested. Using the phase relations between ${\Delta}$-Y transformer in power operation part, gate pulse of the converter is generated with real time process so that microprocessor may share its time to control algorithms efficiently. The firing angle of the converter is smoothly controlled in the range of 0 $^{\dirc}$ to 180$^{\dirc}$ with a fast respone and a constant open loop gain, even for the case where the converter is fed by a weak AC system of unregulated frequency. The hardware and software control circuit implementation built around a 80286 microprocessor is discussed, and the experimental results are given. This scheme uses less hardware components and has higher dynamic performance in variable speed DC drive applications.

• 한국병원경영학회지
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• 제12권2호
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• pp.25-42
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• 2007

To identify characteristics of elderly inpatients who had long term hospitalization in a general hospital, this study categorized into two groups who were hospitalized for less than 30 days and a group hospitalized for more than 30 days. To compare the groups the independent variables were the sociodemographical characteristics, the medical care utility characteristics, and the disease characteristics and finally analyzed factors affecting the hospitalization period. The data of 18,727 inpatients who were older than 65 years of age by the year 2005 were used and the data were analyzed using SPSS for Windows 12.0. With the results, it is necessary to provide intensive and positive management to elderly inpatients who belong to the more than 30 days group and also necessary to share roles and functions of hospital by medical network with local hospitals and clinics in order to manage long-term elderly inpatients and offer continuous post-management to discharged patients by encouraging them to use a long-term care center or by implementing an early discharge program. This study should provide many studies on how to manage the period of hospitalization efficiently on long-stay elderly inpatients in the future.

• 한국콘텐츠학회논문지
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• 제7권12호
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• pp.238-244
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• 2007

최근 ATM 포럼에서 승인한 GFR(Guaranteed Frame Rate) 서비스는 ATM 망에서 TCP/IP 트래픽을 효율적으로 서비스하는 중요한 서비스가 될 것으로 기대된다. GFR 서비스는 프레임 단계에서 최소 대역 서비스를 보장할 뿐 아니라 가용 대역을 공평하게 사용하도록 지원한다. 본 논문에서는 GFR 서비스를 위한 새로운 셀 스케쥴링 알고리즘을 제안한다. 제안된 알고리즘은 VC에 우선순위를 제공하고 버퍼에 있는 좀더 서비스를 받지 못한 셀에 좀더 높은 우선순위를 부여한다. 높은 우선순위의 VC들은 낮은 우선순위의 VC들 보다 더 많은 서비스를 받는다. 제안된 알고리즘은 GFR VC에 MCR 보장과 공평 대역 공유를 제공할 수 있다. 시뮬레이션 결과는 제안된 셀 스케줄링 알고리즘이 TCP 출력과 공평성 면에서 기존의 알고리즘 보다 우수한 성능을 제공함을 보여주고 있다.

• 한국정보통신학회논문지
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• 제9권5호
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• pp.973-980
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• 2005

본 논문에서는 ABR(Available Bit Rate) 트래픽의 흐름제어를 방식들을 분석하고, 지연이 큰 PNNI망에서 VS/VD 스위치를 이용하여 효율적으로 ABR 트래픽을 제어하여, 공평한 전송율을 계산할 수 있는 알고리즘을 제안하였다. 제안된 알고리즘에서는 전송율을 계산하기 위하여 정확하고 공평한 분배를 계산할 수 있는 ER(Explicit Rate) 방식의 FMMRA(Fast Max-Min Rate Allocation)를 사용하였다. 그리고, 지연이 많이 된 상태에서도 큐에 있는 셀을 서비스하고 드레인 하기 위하여, VD에서 VS로 전달된 큐 길이 정보를 이용하여 전송율을 계산함으로서 공평한 셀 서비스 분배를 할 수 있었다. 컴퓨터 시뮬레이션을 통하여 제안된 알고리즘의 성능을 평가하였으며, 그 결과 만족할만한 성능을 얻을 수 있었다.

• KIEAE Journal
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• 제16권5호
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• pp.5-11
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• 2016

Purpose: Residents in deteriorated residential areas of Seoul have suffered from parking shortage problem. Since it is almost impossible to supply new parking, it is critical to find a way to efficiently utilize existing parking spaces. This study proposes utilizing unused parking spaces in apartment complexes so that residents in multi-unit or multi-family houses can share those parking spaces. Method: Spatial scope of this research is limited to multiplex-clustered neighborhood and apartment complex in Seoul. To identify the nature of parking problem, we reviewed current parking situations in residential areas and policies from the Seoul Metropolitan Government. To understand the amount of parking spaces required to solve parking shortages in multiplex-clustered neighborhoods, this study analyzed car ownership per household and available parking spaces in old residential areas. Then we were able to apprehend the amount of parking spaces that could be used for residents in aged multiplex-clustered areas. Result: Our analysis shows a great potential to utilize surplus parking spaces from apartment complexes for solving parking problems in multiplex-clustered neighborhoods.

• Journal of Communications and Networks
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• 제16권6호
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• pp.592-599
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• 2014

Cloud computing enables users to easily store their data and simply share data with others. Due to the security threats in an untrusted cloud, users are recommended to compute verification metadata, such as signatures, on their data to protect the integrity. Many mechanisms have been proposed to allow a public verifier to efficiently audit cloud data integrity without receiving the entire data from the cloud. However, to the best of our knowledge, none of them has considered about the efficiency of public verification on multi-owner data, where each block in data is signed by multiple owners. In this paper, we propose a novel public verification mechanism to audit the integrity of multi-owner data in an untrusted cloud by taking the advantage of multisignatures. With our mechanism, the verification time and storage overhead of signatures on multi-owner data in the cloud are independent with the number of owners. In addition, we demonstrate the security of our scheme with rigorous proofs. Compared to the straightforward extension of previous mechanisms, our mechanism shows a better performance in experiments.