• 한국정보통신학회논문지
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• 제18권3호
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• pp.526-534
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• 2014

본 논문에서는 UWB 기술 기반 WiMedia Distributed Medium Access Control (D-MAC) 프로토콜에서, 디바이스들의 이동성으로 인해 발생하는 Distributed Reservation Protocol (DRP) 예약 충돌 현상을 분석한다. 그리고 DRP 예약 충돌 시 발생하는 성능 저하를 감소시키기 위해 Conflict Resolution (CR) 방식과 DRP 릴레이 기술을 제안한다. 본 논문에서 제안하는 DRP 릴레이 프로토콜은 충돌대상 디바이스에게 예약된 자원을 유지할 수 있도록, DRP 예약 충돌 시 릴레이 노드를 경유하여 다른 Indirect Link 링크를 빠르게 예약할 수 있는 분산적인 자원 예약 프로토콜을 제안한다. 이동성 환경을 고려한 시뮬레이션 결과는 CR 기술과 함께 DRP 릴레이 기술을 적용하여, 디바이스들의 이동성이 증가하더라도 수율 감소를 방지할 수 있음을 나타내었다.

• Journal of Power Electronics
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• 제14권6호
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• pp.1100-1108
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• 2014

Modular multilevel converters (MMCs) have emerged as the most promising topology for high and medium voltage applications for the coming years. However, one particular negative characteristic of MMCs is the existence of circulating current, which contains a dc component and a series of low-frequency even-order ac harmonics. If not suppressed, these ac harmonics will distort the arm currents, increase the power loses, and cause higher current stresses on the semiconductor devices. Repetitive control (RC) is well known due to its distinctive capabilities in tracking periodic signals and eliminating periodic errors. In this paper, a novel circulating current control scheme base on RC is proposed to effectively track the dc component and to restrain the low-frequency ac harmonics. The integrating function is inherently embedded in the RC controller. Therefore, the proposed circulating current control only parallels the RC controller with a proportional controller. Thus, conflicts between the RC controller and the traditional proportional integral (PI) controller can be avoided. The design methodologies of the RC controller and a stability analysis are also introduced. The validity of the proposed circulating current control approach has been verified by simulation and experimental results based on a three-phase MMC downscaled prototype.

• 농업과학연구
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• 제47권4호
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• pp.885-901
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• 2020

A forest watershed management project was introduced in 2004 to develop ecologically sound forest watersheds. It includes landslide prevention and erosion control, water resource management, landscape development, and forest resource management. However, it has been managed fragmentarily and inefficiently, far from the original intents. This study investigated current status, problems, and improvement measures of the project. Literature reviews were conducted on forest watershed management in Korea and other countries, and surveys were conducted on 201 erosion control experts. When introduced, the forest watershed management project was well planned and implemented as intended. It later turned to focus only on disaster prevention such as erosion control dams and stream conservation measures. The survey results showed that a majority (89% and 86%) of surveyees wanted increases in the project period and budget. They also responded that conflicts with local residents (51%) and determining project locations (32%) were the most difficult tasks when implementing the projects, and only 36% kept project records. To plan and implement the projects as intended, the following suggestions should be considered: (1) establishment of a solid legal foundation and improvement of the erosion control practices law; (2) increase in the project period (from 1 to 2 - 3 years) and budget; (3) development of a manual for project site selection and guidelines; (4) monitoring and systematic information management; and (5) development of spatial analysis tools for watershed analysis and management.

• 조명전기설비학회논문지
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• 제24권7호
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• pp.9-19
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• 2010

Fuel cell (FC) distributed generation (DG) is gradually becoming more attractive to mainstream electricity users as capacity improves and costs decrease. New technologies including inverters are becoming available to provide a uniform standard interconnection of DGs with an electric power system. Some of the operating conflicts and the effect of DG on power quality are addressed and investigated through simulations on a real distribution network with an FC power plant. The results of these simulations have proved load tracking capability following the real and reactive power change of the load and have shown the flow of overcurrent from an FC power plant during the ground fault of a distribution line.

• 전자공학회논문지A
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• 제31A권3호
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• pp.53-67
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• 1994

This paper describes the design of a high-level synthesis system. SODAS-VP. which automatically generates hardwares executing operation sequences in pipelined fashion.Target architecture and clocking schemes to drive pipelined datapath are determined, and the handling of pipeline hazards which degrade the performance of pipeline is considered. Partitioning of an operation into load, operation, and store stages, each of which is executed in partitiones control step, is performend. Pipelinecl hardware is generated by handling pipeline hazards with internal forwarding or delay insertion techniques in partitioning process and resolving resource conflicts among the partitioned control steps with similarity measure as a priority function in module allocation process. Experimental results show that SODAS-VP generates hardwares that execute faster than those generated by HAL and ALPS systems. SODAS-VP brings improvement in execution speed by 17.1% and 7.4% comparing with HAL and ALPS systems for a MCNC benchmark program, 5th order elliptical wave filter,respectively.

• Wind and Structures
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• 제29권6호
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• pp.489-497
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• 2019

Wind-adaptable design (WAD) provides a new method for super-tall buildings to lessen design conflicts between architectural prerequisites and aerodynamic requirements, and to increase the efficiency of structural system. Compared to conventional wind-resistant design approach, the proposed new method is to design a building in two consecutive stages: a stage in normal winds and a stage during extreme winds. In majority of time, the required structural capacity is primarily for normal wind effects. During extreme wind storms, the building's capacity to wind loads is reinforced by on-demand operable flow control measures/devices to effectively reduce the loads. A general procedure for using WAD is provided, followed by an exploratory case study to demonstrate the application of WAD.

• 한국데이타베이스학회:학술대회논문집
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• 한국데이타베이스학회 1995년도 제4회 멀티미디어 산업기술 학술대회 논문집
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• pp.132-142
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• 1995

Development in multimedia technology enhances Computer Supported Cooperative Work(CSCW) such as tole-conferencing and tole-education. These applications are also called groupware applications and usually composed of AM conferencing module and shared working space such as group editors. Through this shared working space users can present, manipulate and save common artifacts interactively. Since users are allowed to operate on common artifacts simultaneously, conflicts between user transactions are bound to happen and can cause unnatural effects on user interfaces. In this paper we reviewed these problems and presented common solutions to concurrency control problems. We also presented Coshed/SAS, a group editor, as an example of groupware applications and related concurrency control problems.

• 대한간호학회지
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• 제36권4호
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• pp.596-603
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• 2006

Purpose. This study examined Korean clinical nurses' intentions to care for SARS patients and identify determinants of the intentions. Theory of planned behavior was the framework to explain the intentions of Korean nurses for SARS patients care. Methods. A convenient sample of six hundreds and seventy nine clinical nurses from four university-affiliated hospitals located in Seoul and in Kyung-gi province was used. Self-administered (83-items) questionnaire was used to collect data. Intentions, attitude, subjective norm, perceive behavioral control, behavioral beliefs, normative beliefs, and control beliefs were the study variables. All items were measured using 7point Likert scale (-3 to +3). Data were analyzed using descriptive statistics, Pearson correlation method, and stepwise multiple regression methods. Results. Intentions and attitudes toward SARS patient care among Korean clinical nurses were moderate, but their subjective norm and perceive behavioral control of SARS patients care were negative. Stepwise multiple regression analysis indicated that attitude toward SARS patient care, perceived behavioral control, subjective norm were the determinants of the intentions for SARS patients care as theory proposed. Among the behavioral beliefs, 'SARS-patient caring would be a new experience', 'during SARS-patient caring, I should be apart from my family', 'after completing SARS-patient caring, I would be proud of myself being able to cope with a stressful event' and 'with my SARS-patient caring, patients could recover from SARS' were the significant determinants. Among the normative beliefs, colleague approval, spouse approval, and physician approval were significant determinants of the intentions. Among the control beliefs, 'SARS-patient caring would be a challenge' 'SARS-patient caring is a professional responsibility', 'tension during the care of SARS patients' and 'support from team members' were the significant determinants of the intentions. Conclusions. Korean clinical nurses in this study were not willing to care for SARS patients and showed negative attitude toward the care. They believed their friends and family were not approved their care for SARS patients. Nurses were in conflicts between professional responsibilities to care for SARS patients and personal safety. This study was the first to understand stress and burden of Korean clinical nurses who are in front line to care for newly developed communicable disease such as SARS. Under the circumstance where several fatal communicable diseases are predictable, conflicts between professional responsibility and their personal risks should be taken into considerations by nurses themselves and by nursing administrators in order to improve quality of care.

• 한국IT서비스학회지
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• 제8권4호
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• pp.175-185
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• 2009

Objectifying claims filed during the warranty period, analyzing the current circumstances and improving on the problem in question is an activity worth doing that could reduce the likelihood of claims to occur, cut down on the costs, and enhance the corporate image of the manufacturer. Existing analyses of claims are confronted with two problems. First, you can't precisely assess the risks of claims involved by means of the value of claims per 100 products alone. Second, even in a normal state, the existing approach fails to capture the probabilistic conflicts that escape the upper control limit of claims, thus leading to wrong control activities. To solve the first problem, this paper proposed that a time series detection concept where the claim rate is monitored based on the date when problems are processed and a hazard function for expression of the claim rate be utilized. For the second problem, this paper designed a model whereby to define a normal state by making use of PID (Proportion, Integral, Differential) and infer by way of a fuzzy concept. This paper confirmed the validity and applicability of the proposed approach by applying methods suggested in the actual past data of warranty claims of a large-scaled automotive firm, unlike hypothetical simulation data, in order to apply them directly in industrial job sites, as well as making theoretical suggestions for analysis of claims.

• 한국대기환경학회지
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• 제16권1호
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• pp.79-87
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• 2000

This study analyzed the regulations concerning odor management or control in Korea, Japan, and developed countries such as USA and Germany. The Korean restriction standards and measurement methods for offensive odor substances are very similar to the Japanese standards and methods promulgated in 1976. Japan promulgated the odor control act and the specific measurement methods of the offensive odor substances in 1973. In Japan, currently, the local governments can establish their own odor restriction areas and proclaim their own standards suitable for their situations. Also, Japan has more strict regulations and more offensive odor substances to be monitored than Korea. The restriction standards of odor in German is quite similar to the permissible limits and standards of air pollutants at emission sources in Korea. Many states in USA are adopting their own restriction standards and measurement methods, e.q., the ambient air pollution standards, organic functionstest methods by dilation, and establishment and addition of air pollution control equipment at emission sources. Finally, this study analyzed the problems of the regulations, standards, and measurement methods concerning the Korean offensive odor management. Since the direct organic fuctions measurement(DOFMM) method is depending upon the personal sensitives of odor substances, the measurement odor value can be equivocal. That is, the odor measurement value by an examines can differ from that by the other examines. Also, there can be conflicts with the measured odor values depending upon the applied measurement methods, e.q., the DOFMM, the dilation method, and the instrumental analysis method.