• 한국인터넷방송통신학회논문지
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• 제11권4호
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• pp.69-74
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• 2011

본 논문에서는 RTLS 기술을 이용한 구제역 예방 시스템과 구제역 지역을 피하기 위한 $A^*$ 알고리즘 기반의 최적 경로 탐색 방법을 제안한다. 제인된 시스템의 주요한 특징 및 기여도는 다음과 같다. 첫째, 제인된 시스템은 가축들의 상태와 위치 정보를 파악하기 위하여 능동형 태그를 기반으로 한다. 둘째, 최적 경로 탐색을 지원하기 위해 $A^*$ 알고리즘 기반으로 새롭게 설계하였다. 제안된 시스템의 성능평가는 모의실험을 통하여 이루어진다. 성능평가를 통하여 제안된 시스템은 최적 경로 탐색 서비스를 효율적으로 지원하였다.

• 한국IT서비스학회지
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• 제18권4호
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• pp.171-190
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• 2019

This study comparatively analyzes the cases of CDMA (Code Division Multiple Access) and WIPI (Wireless Internet Platform for Interoperability) to find out the success and failure factors of technology policies in the field of mobile communication industry. For this purpose, the two cases are analyzed through a new analysis framework, which is made by combining System of Innovation with a range of variables derived from precedent studies, such as external environment, institutions, technological system, governance structure, and interactions of actors. The results of analysis show that in the CDMA case, the following factors led to success ; Korea made good use of the external opportunities in the early stage of digital communication technology and adopted a suitable governance structure for the technological system. Main actors in Innovation System had strong will for success and engaged in cooperative interaction. For the WIPI, however, the timing of technology policy was inappropriate and a unsuitable governance structure for technological system was chosen because of path dependence. The Innovation System failded to respond efficiently to the situation where conflicts among actors had intensified, US trade pressure had increased and innovative smartphones emerged. The results of this study provide the practical implications for the success of technology policy; namely it is important to choose a governance structure that suits the external environment and characteristics of technology and to activate cooperative interactions among actors in Innovation System.

• 한국구조물진단유지관리공학회 논문집
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• 제5권3호
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• pp.233-244
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• 2001

Stress-strain behaviour of soil varies based on stress path and stress history. There has been few study on the characteristics of yielding curve which has anisotropic compression stress history in decomposed granite soil. During this study, various stress path tests in previous anisotropic compression stress history are performed on compacted decomposed granite soil sampled at Iksan, Chonbuk. Yielding points are determined from various stress-strain curves (${\eta}-{\varepsilon}$, ${\eta}$-v, and ${\eta}$-k, ${\eta}$-W curves). Stress-strain curve is certified which shows yielding point very clearly. The shape and characteristics of anisotropic compression yielding curves are examined. The main results are summarized as follows : 1) p' constant and compressive direction in stress paths, which has experienced previous anisotropic compression stress history, shows relatively dear yielding points. 2) Yielding curves defined from ${\eta}$-k and ${\eta}$-W curve show almost perfect ellipse. 3) Directions of plastic strain incremental vector($dv^p/d{\varepsilon}^p$) are not perpendicular to yielding curve.

• 한국군사과학기술학회지
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• 제13권5호
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• pp.824-830
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• 2010

It is not easy job to find a underwater target using sonar system in the ASW operations. Many researchers have tried to solve anti-submarine search problem aiming to maximize the probability of detection under limited searching conditions. The classical 'Search Theory' deals with search allocation problem and search path problem. In both problems, the main issue is to prioritize the searching cells in a searching area. The number of possible searching path that is combination of the consecutive searching cells increases rapidly by exponential function in the case that the number of searching cells or searchers increases. The more searching path we consider, the longer time we calculate. In this study, an effective algorithm that can maximize the probability of detection in shorter computation time is presented. We show the presented algorithm is quicker method than previous algorithms to solve search problem through the comparison of the CPU computation time.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2000년도 추계학술대회논문집
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• pp.208-214
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• 2000

Reduction of structure-borne noise of the compartment in a car is an important task in automotive engineering. Transfer path analysis using vibroacoustic reciprocity technique or multiple path decomposition method has generally been used for structure-borne noise path analysis. These methods are useful in solving particular problem but do not quantify the effectiveness of vibration isolation of each isolator of a vehicle. To quantify the effectiveness of vibration isolation, the vibrational power flow has been used for a simple isolation system or a laboratory based isolation system. It is often difficult to apply the vibrational power flow technique to the complex isolation system like a car. In this paper, a simple equation is derived for calculation of the vibrational power flow of an isolation system with multiple isolators such as a car. It is successfully applied to not only quantifying the relative contributions of eighteen isolators but also reducing structure-borne noise of a passenger car. According to the results, the main contributor of eighteen isolators is the rear roll mount of an engine. The reduced structure-borne noise level is about 5dBA.

• Ocean Systems Engineering
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• 제12권3호
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• pp.359-384
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• 2022

We develop in this work a new well-balanced preserving-positivity path-conservative central-upwind scheme for Saint-Venant-Exner (SVE) model. The SVE system (SVEs) under some considerations, is a nonconservative hyperbolic system of nonlinear partial differential equations. This model is widely used in coastal engineering to simulate the interaction of fluid flow with sediment beds. It is well known that SVEs requires a robust treatment of nonconservative terms. Some efficient numerical schemes have been proposed to overcome the difficulties related to these terms. However, the main drawbacks of these schemes are what follows: (i) Lack of robustness, (ii) Generation of non-physical diffusions, (iii) Presence of instabilities within numerical solutions. This collection of drawbacks weakens the efficiency of most numerical methods proposed in the literature. To overcome these drawbacks a reformulation of the central-upwind scheme for SVEs (CU-SVEs for short) in a path-conservative version is presented in this work. We first develop a finite-volume method of the first order and then extend it to the second order via the averaging essentially non oscillatory (AENO) framework. Our numerical approach is shown to be well-balanced positivity-preserving and shock-capturing. The resulting scheme could be seen as a predictor-corrector method. The accuracy and robustness of the proposed scheme are assessed through a carefully selected suite of tests.

• 드라이브 ㆍ 컨트롤
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• 제15권4호
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• pp.11-16
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• 2018

Pilot operated control valve for $CO_2$ refrigerant is a valve that can perform various functions according to the user's intention by replacing pilot units, widely used for flow rate, pressure, and temperature control of refrigeration and air conditioning systems. In addition, $CO_2$ refrigerant, that requires high pressure and low critical temperature, can be installed and used in all positions of the refrigeration system, regardless of high or low pressure. In this paper, response characteristics are modeled and analyzed based on behavior of the main piston of the pilot-operated control valve. Although various factors influence operation of the main piston, this paper analyzes the effect of equilibrium pressure depending on valve installation position and application, and inlet and outlet orifice size of the load pressure feedback chamber to determine feedback characteristics of the main piston. As a result, it was possible to quantitatively analyze the effect of change in equilibrium and load pressure feedback chamber flow path size on the change in main piston dynamic and static characteristics.

• 한국의류학회지
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• 제24권4호
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• pp.549-559
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• 2000

In a few studies about product involvement there was confusion in the construct of involvement especially in association with importance. Due to the confusion of the construct unanticipated and inconsistent results were reported in some cases. So this study was mainly to identify the relationship between clothing importance and clothing involvement and also investigated the casual relationships among consumers n, value, clothing importance, clothing involvement fashion opinion leadership, and shopping behavior. The data were collected from 429 female adults using questionnaire, and were analysed with actor and path analysis. Results can be summarized as follows. First, clothing importance was the separate concept from clothing involvement, though they were closely related. Second. it was revealed that the main casual path was valuerlongrightarrowclothing importancelongrightarrowclothing involvementlongrightarrowfashion opinion leadership, shopping preference, shopping frequency, and shopping time. On the whole, the affective dimension of clothing involvement mainly affected them, and consumer's age negatively affected fashion opinion leadership and shopping behavior.

• 전기전자학회논문지
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• 제13권1호
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• pp.94-100
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• 2009

In recent years, the wireless mesh network (WMN) has been an emerging technology to provide Internet access to fixed and mobile wireless devices. The main goal of this paper is the design and simulation of a new MAC protocol based on the multi-path routing information for wireless mesh networks. The information about multiple paths discovered in the network layer is exploited by the MAC layer in order to forward a frame over the best hop out of multiple hop choices. The performance of our approach is compared with conventional 802.11 MAC through the simulation. The results show that our scheme exhibits a significantly better performance rather than conventional 802.11 MAC protocol in terms of packet overhead, end-to-end throughput and delay.

• 한국지능시스템학회:학술대회논문집
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• 한국퍼지및지능시스템학회 2003년도 ISIS 2003
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• pp.500-503
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• 2003

The navigation problem of robot is one of the main themes to deal with conficts or interferences between obstacles and the robot itself In this case, while the robot avoids obstacles on the space, the passage route should be determined efficiently. In order to solve problems above, we have come up with the distance field space medel (DFM) and then, under known environment, we have presented the distance field A algorithm for passage route path search. In this research, the method of performing the 3-dimensional passage route path search of robot under unknown environment is proposed. It is shown that the authors can build the distance search model the does not need space division by taking into account of sensor information to a distance field space model, and constructing this information as virtual obstacle information.