• 한국통신학회논문지
• /
• 제19권6호
• /
• pp.1038-1045
• /
• 1994

본 논문에서는 CAM에서 발생하는 모든 PSF(Pattern Sensitive Fault)를 검사하기 위한 알고리즘과 테스트회로를 설계하였다. 즉, 짧은 시간에 최소의 부가회로를 이용하여 외부의 장비에 의존하지 않고 테스트하는 내장 테스트회로를 설계하였다. 부가적으로 첨가된 회로로는 병렬비교기와 오류검출기가 있고, 병렬테스팅을 위해서 수정된 디코더를 사용하였다. 또한, 효과적인 테스트패턴을 구하기 위해 Eulerian path의 구성방법에 대해서도 연구를 수행하였다. 결과적으로, 본 논문에서 사용한 알고리즘을 사용하면 워드수에 관계없이 324+2b(b:비트수) 만큼의 동작으로 CAM의 모든 내용을 테스트할 수 있다. 전체 회로중에서 테스트회로가 차지하는 면적은 약 7.5%정도가 된다.

• 산업경영시스템학회지
• /
• 제39권2호
• /
• pp.46-53
• /
• 2016

In mobile communication systems, location management deals with the location determination of users in a network. One of the strategies used in location management is to partition the network into location areas. Each location area consists of a group of cells. The goal of location management is to partition the network into a number of location areas such that the total paging cost and handoff (or update) cost is a minimum. Finding the optimal number of location areas and the corresponding configuration of the partitioned network is a difficult combinatorial optimization problem. This cell grouping problem is to find a compromise between the location update and paging operations such that the cost of mobile terminal location tracking is a minimum in location area wireless network. In fact, this is shown to be an NP-complete problem in an earlier study. In this paper, artificial bee colony (ABC) is developed and proposed to obtain the best/optimal group of cells for location area planning for location management system. The performance of the artificial bee colony (ABC) is better than or similar to those of other population-based algorithms with the advantage of employing fewer control parameters. The important control parameter of ABC is only 'Limit' which is the number of trials after which a food source is assumed to be abandoned. Simulation results for 16, 36, and 64 cell grouping problems in wireless network show that the performance of our ABC is better than those alternatives such as ant colony optimization (ACO) and particle swarm optimization (PSO).

• 농업과학연구
• /
• 제50권2호
• /
• pp.207-218
• /
• 2023

Duck farming restriction refers to a program in which duck farms suspend their operations for a certain period at times when the risk of avian influenza (AI) is high and receive compensation from the Korean government. This study analyzed the effect of this duck farming restriction on the incidence of AI using data on regional AI incidence rates, the program participation rate, and characteristics of poultry farming in 2016 (before the implementation of the restriction), as well as data from 2020 and 2021 (when new AI outbreaks occurred). In this study, the treatment group was divided into five subgroups according to the policy participation rate and a difference-in-difference (DID) estimation was conducted using certain covariates, in this case the average number of ducks raised, the land area, the number of high-susceptibility farms, the number of low-susceptibility farms, the average number of farms within a 3 km radius, the average distance to the nearest farm, and a year dummy. The results showed that when more than 30% of all duck farms in a region participated in the farming restriction, it had a statistically significant effect on the incidence of AI. Specifically, when more than 30, 40, 50, and 60% of all duck farms participated in the farming restriction, the AI incidence rate decreased by 0.7184, 1.0025, 1.5844, and 1.5843%p, respectively.

• 한국언론정보학보
• /
• 제16권
• /
• pp.7-35
• /
• 2001

This paper examined the present status of local newspapers and their problems. It was originated from the fact that the number of local newspapers have continuously increased since 1987 when the establishment of newspaper company became convenient, and that as a result the competition among local newspapers became high and several unexpected negative out comes brought forth. The analytical focus of this parer was placed on the internal and external environments surroundings local newspapers. The results showed followings: There are too many local newspapers competing each other in the same area; Financial crises mainly caused by over-competition are critical; Ownership and business operations are too distorted to take the socially expected role of newspapers; Many newspapers are often mobilized for the political and economic purposes of the owner; Market rules and advertising inducement practices are likely to be violated because of over-competition; the morales of Journalists are decreased and work qualities are deteriorated. On the basis of these findings this paper suggested several policy implications: The structure of ownership has to be changed into a direction where a few major stock-holders cannot influence the whole business operations; Top managers have to change their business motivation from profit-seeking to profit-sharing; business practices has to be open and clean; New editorial polices attracting readers have to be established; qualified Journalists have to be recruited and they have to be retrained throughout their career life.

• 산업공학
• /
• 제16권4호
• /
• pp.450-462
• /
• 2003

In this paper, we deal with a process and layout design for producing a planned amount of Sikhye in a given limited time period under a reasonable production schedule. We represent a Sikhye production line as a vector N, the element of which denotes the number of tanks required in each process and our objective is to find an appropriate vector which minimizes the total investment cost. We suggest a systematic method for finding an appropriate N and an appropriate layout to N. In detail, first, we decide the required sequence of processes and the required operations for each process and we estimate standard operating times. Second, constructing a precedence diagram, we find a critical path in order to reduce the total production lead time for a batch of Sikhye. Third, given a limited N space, we manage to construct manually each production schedule using both the processing times of the critical operations and transfer times. Finally, we find an optimal vector N which gives a minimum investment cost and meets both the time constraint and quantity constraint. In addition, with the estimated relative size of each tank, we suggest an appropriate conceptual layout design including an expansion area for future demands, based on the span technique used in the field of architectural design.

• 한국CDE학회논문집
• /
• 제14권1호
• /
• pp.18-24
• /
• 2009

This paper proposes an analytical method of evaluating the maximum error by modeling the exact tool path for the tool traverse singular region in five-axis machining. It is known that the NC data from the inverse kinematics transformation of 5-axis machining can generate singular positions where incoherent movements of the rotary axes can appear. These lead to unexpected errors and abrupt operations, resulting in scoring on the machined surface. To resolve this problem, previous methods have calculated several tool positions during a singular operation, using inverse kinematics equations to predict tool trajectory and approximate the maximum error. This type of numerical approach, configuring the tool trajectory, requires much computation time to obtain a sufficient number of tool positions in a region. We have derived an analytical equation for the tool trajectory in a singular area by modeling the tool operation into a linear and a nonlinear part that is a general form of the tool trajectory in the singular area and that is suitable for all types of five-axis machine tools. In addition, we have evaluated the maximum tool-path error exactly, using our analytical model. Our algorithm can be used to modify NC data, making the operation smoother and bringing any errors to within tolerance.

• 한국경영과학회:학술대회논문집
• /
• 한국경영과학회 2004년도 추계학술대회 및 정기총회
• /
• pp.13-16
• /
• 2004

This paper deals with a one-searcher multi-target search problem where targets with different detection priorities move in Markov processes in each discrete time over a given space search area, and the total number of search time intervals is fixed. A limited search resource is available in each search time interval and an exponential detection function is assumed. The searcher can obtain a target detection award, if detected, which represents the detection priority of target and is non-increasing with time. The objective is to establish the optimal search plan which allocates the search resource effort over the search areas in each time interval in order to maximize the total detection award. In the analysis, the given problem is decomposed into intervalwise individual search problems each being treated as a single stationary target problem for each time interval. An associated iterative procedure is derived to solve a sequence of stationary target problems. The computational results show that the proposed algorithm guarantees optimality.

• 한국철도학회논문집
• /
• 제10권1호
• /
• pp.16-21
• /
• 2007

Along with the opening of the high speed railroad in 2004, the number of long tunnels constructed is increasing and will be continued. In this respect, the fro inside the tunnels is a main cause of drastic damages to both facilities and lives of passengers on board, especially more severe consequences are expected if the fire occurs on a train in urban area. Even though, the threat to human lives due to the increasing number of tong tunnels and increasing train operation times inside such tunnels is getting bigger, the studies to measure safety of the tunnel and to enhance the safety of passengers have not been carried out enough in Korea. Therefore, in this paper, we will use the probabilistic method to predict the average number of deaths of passengers in case of fire on a train iii tunnel, and show the potential risk to passengers which can be a guide for safer design of tunnels to be constructed.

• Journal of Chest Surgery
• /
• 제49권sup1호
• /
• pp.53-59
• /
• 2016

Background: The purpose of this study is to evaluate the concentration of cardiovascular surgical procedures in a metropolitan area and investigate the perception of specialists regarding governmental policies to resolve this imbalance. Methods: From March to May 2015, surveys were distributed to members of the Thoracic and Cardiovascular Surgery Association. The final pool of research subjects consisted of 75 respondents. Subjects were queried regarding the concentration of cardiovascular operations in metropolitan areas, alternatives to the imbalance, and governmental policies to resolve the inequalities. Results: Survey participants responded that South Korea needs governmental policies to alleviate the concentration of cardiovascular surgery patients in large metropolitan hospitals. Participants agreed that the freedom to choose medical institutions and improved accessibility to metropolitan hospitals due to advanced transportation systems were some of the causes for the concentration. A majority (98.7%) of respondents thought establishing thoracic and cardiovascular surgery centers in provinces was an appropriate solution to alleviate the concentration. Thoracic and cardiovascular surgery specialists were ranked as the number one group on which to focus development. Conclusion: Developing and carrying out policies to establish thoracic and cardiovascular surgery centers in provinces will alleviate the regional imbalance in available heart surgery services and an overall improvement in cardiovascular disease treatment in South Korea.

• 한국콘텐츠학회논문지
• /
• 제9권7호
• /
• pp.57-66
• /
• 2009

Zigbee는 USN에서 쓰고 있는 대표적인 통신 표준이며 다양한 어플리케이션에 쓰이고 있다. Zigbee 프로토콜은 하나의 PAN망 안에서 어드레스를 부여하는데 DAA라는 방법을 이용을 하는데 이는 16Bit어드레스 구역을 Depth에 따라 일정한 크기의 블록으로 나누어서 각각의 노드에게 할당을 하는 방식이다. 그러나 이 방식은 노드수가 Depth가 증가함에 따라서 하나의 Depth에 부여하는 최대 Router수의 지수승으로 증가를 하기 때문에 16Bit로 부여할 수 있는 어드레스에 제한이 생긴다. 따라서 넓은 지역이나 음영지역이 많은 곳처럼 많은Router수를 가지고 Depth가 큰 네트워크를 구성하기가 힘들다. 또한 하나의 PAN망 안에서 동작하기 때문에 여러 PAN을 하나의 네트워크로 구성하기가 힘들다. 본 논문에서는 Zigbee 기반의 네트워크를 확장하여 여러 PAN망을 하나의 네트워크로 구성할 수 있고 Router수와 Depth에 제한이 덜하여 넓은 지역을 묶을 수 있는 새로운 어드레스 방식과 라우팅 방법을 제안을 하였다. 그리고 이를 실험을 통하여 그 동작을 확인하고 실증 시험을 통하여 활용할 수 있음을 보였다.