• 정보처리학회논문지C
• /
• 제9C권2호
• /
• pp.221-226
• /
• 2002

본 논문에서 제안한 사이클링 패킷 폐기 메커니즘은 사이클 사이의 트래픽 변화를 예측하여 패킷 폐기를 적응적으로 처리할 수 있다. 따라서 제안된 메커니즘은 RIO 메커니즘의 단순 폐기율 적용에 대한 단점을 보완하고, 동적 엄격 패킷 폐기 메커니즘의 예측 가능한 오류율을 최소화하였다. 시뮬레이션을 수행하여, 망 트래픽의 상태에 따라 동적으로 변하는 전송가능 폐기순위에 따른 처리율과 패킷 폐기율을 분석하였다. 시뮬레이션을 분석한 결과 제안된 메커니즘은 트래픽의 양에 상관없이 각 AF 클래스의 폐기순위를 엄격하게 적용하고 폐기순위에 따른 패킷 전송능력이 개선하였음을 증명하였다.

• 제어로봇시스템학회논문지
• /
• 제11권2호
• /
• pp.175-185
• /
• 2005

The scheduling methods of the distributed real-time systems have been proposed. However, they have some weak points. They did not schedule both sporadic and periodic tasks and messages at the same time or did not consider the end-to-end constraints such as precedence relations between sporadic tasks. This means that system scheduling must guarantee the constraints of practical systems and be applicable to them. This paper proposes a new scheduling method that can be applied to more practical model of distributed real-time systems. System model consists of sporadic and periodic tasks with precedence relations and sporadic and periodic messages and has end-to-end constraints. The proposed method is based on a binary search-based period assignment algorithm, an end-to-end laxity-based priority assignment algorithm, and three kinds of schedulability analysis, node, network, and end-to-end schedulability analysis. In addition, this paper describes the application model of sporadic tasks with precedence constraints in a distributed real-time system, shows that existing scheduling methods such as Rate Monotonic scheduling are not proper to be applied to the system having sporadic tasks with precedence constraints, and proposes an end-to-end laxity-based priority assignment algorithm.

• 인지과학
• /
• 제23권3호
• /
• pp.389-408
• /
• 2012

감각적 경험을 언어로 기술하면 그 경험에 관한 감각적 기억이 저하되는데, 이러한 현상을 일컬어 언어 장막(verbal overshadowing) 효과라고 한다. Schooler(2002)[1]는 언어화로 인해 정보처리 방식이 전역적 처리에서 국지적 처리로 전환되기 때문에 언어 장막이 발생한다고 제안하였다. 본 연구에서는 이러한 정보처리의 전환이 실제로 일어나는가를 검증하고자 얼굴 자극에 대한 기억을 요구하고 이를 토대로 언어적 묘사를 한 직후에 전역 처리와 국지 처리를 비교할 수 있는 Navon 과제를 실시하였다. 얼굴 재인 과제에서는 참가자들에게 외워야 하는 얼굴을 제시한 후 그 얼굴에 대한 언어화를 요구하였으며, 얼굴 재인 과제를 수행한 직후에 Navon 과제를 수행하도록 하였다. 그 결과, 얼굴 재인 과제에서는 언어화를 한 묘사 집단에서 언어화를 하지 않은 통제 집단보다 낮은 재인률을 보이는 언어 장막 효과가 나타났다. Navon 과제에서는 통제 집단이 전역수준의 정보가 국지 수준의 정보보다 우세하게 처리되는 전역 선행성(global precedence)을 보인 반면에, 묘사 집단은 전역 수준의 정보보다 국지 수준의 정보를 더 우세하게 처리하는 국지 선행성을 보였다. 이는 얼굴을 언어화함으로써 정보처리의 방식이 전역적인 방향에서 국지적인 방향으로 전환되고, 그 결과로서 얼굴에 대한 재인이 손상된 것임을 시사한다.

• 대한전자공학회:학술대회논문집
• /
• 대한전자공학회 1998년도 추계종합학술대회 논문집
• /
• pp.1239-1242
• /
• 1998

In television stereo system, to produce a realistic sound effect is very difficult because the distance between stereo speakers is very narrow. Many signal processing methods of widening the sound image for spatial impression have been studied. One of the methods of widening the sound image is using the Precedence Effect by reflected sound. However, this method does not work effectively in lower frequencies because of directivity of a speaker. In this paper, we propose an effective method of expanding stereo image using Precedence Effect and Phase Shifting method to produce a whole band frequency sound expansion. In experiments, we confirm the usefulness of the proposed stereo sound image expansion system.

• 제어로봇시스템학회:학술대회논문집
• /
• 제어로봇시스템학회 1993년도 한국자동제어학술회의논문집(국제학술편); Seoul National University, Seoul; 20-22 Oct. 1993
• /
• pp.391-394
• /
• 1993

A new approach using a Hopfield type neural network to solve line balancing problems for manufacturing planning is proposed. The energy function of the network to evaluate solutions is composed of three terms;(a) an operation should be processed at one and only one workstation, (b) the precedence-relationship between two operations shoud be satisfied, and (c) the cycle-time of operations should be minimized. It is shown that the network can solve the line balancing problems but not always because of the difficulty to keep the precedence-relationship. Therefore, a method to keep the precedence-relationship by software logic is proposed and it is verified that the line-balancing prblems can be solved with high probability.

• 품질경영학회지
• /
• 제22권1호
• /
• pp.169-178
• /
• 1994

Nonparametric tests for comparing two treatments when data are subject to unequal patterns of censorship are discussed. Best precedence test proposed by Slud can be viewed as a nice alternative test comparing with weighted log-rank tests, not to mention the advantage of short experimental period. This research revises some missing parts of Slud's test and examines the asymptotic power of it under the nonproportional hazard alternatives through the simulation. The simulation studies show best precedence test has reasonable power in the sense of robustness under nonproportional hazard alternatives and could be recommended at such situation.

• 대한산업공학회지
• /
• 제24권2호
• /
• pp.185-197
• /
• 1998

Engineering design involves the specification of many variables that define a product, how it is made, and how it behaves. Before some variables can be determined, other variables must first be known or assumed. This fact implies a precedence order of the variables, and of the tasks of determining these variable consequently. Moreover, design of complex systems may involve a large number of design activities. In this paper, the activity-activity incidence matrix is considered as a representation of design activity analysis which mainly focuses on the precedence constraint. In order to analyze the activity-activity incidence matrix, a heuristic algorithm is proposed, which transforms an activity-activity, parameter-formula, and parameter-parameter incidence matrix into a lower triangular form. The analysis of the structured matrices can not only significantly reduce the overall project complexity by reorganizing few critical tasks in practice, but also aims at obtaining shorter times considering the solution structure by exploring concurrency.

• 대한전기학회:학술대회논문집
• /
• 대한전기학회 2005년도 추계학술대회 논문집 전력기술부문
• /
• pp.258-260
• /
• 2005

Recently, it is focused on a methodology to estimate a order of precedence investment in distribution power system under competitive electricity market. This paper suggests methodology to evaluate the order as using a sensitivity of system interruption cost in distribution system regarding a failure rate of distribution components. In this paper, by using one of feeder in RBTS model, the order is assessed to compare valuation about sensitivity of interruption cost with valuation about sensitivity of estimated reliability indices. In conclusion, it is shown that results of precedence investment based on each methods are difference.

• 제어로봇시스템학회논문지
• /
• 제18권4호
• /
• pp.302-307
• /
• 2012

Real-time systems perform periodic tasks and real-time aperiodic tasks such as alarm processing. Especially the periodic tasks included in control systems such as robots have precedence relationships among them. This paper proposes a new scheduling algorithm based on topological sort and residual time. The precedence relationships among periodic tasks are translated to the priorities of the tasks using topological sort algorithm. During the execution of the system the proposed scheduling algorithm decides on whether or not a newly arrived real-time aperiodic task is accepted based on residual time whenever the aperiodic task such as alarm is arrived. The proposed algorithm is validated using examples.

• 대한산업공학회지
• /
• 제19권1호
• /
• pp.1-17
• /
• 1993

It is well known that an assembly operation is usually constrained by the geometric interference between parts. These constraints are normally presented as AND/OR precedence relationships. To find a feasible assembly sequence which satisfies the geometric constraints is not an easy task because of the TSP(Traveling Salesman Problem) nature with precedence constraints. In this paper, we developed an automated system based on Neural Network for generating feasible assembly sequences. Modified Hopfield and Tank network is used to solve the problem of AND/OR precedence-constrained assembly sequences. An economic assembly sequence can be also obtained by applying the cost matrix that contains cost-reducing factors. To evaluate the performance and effectiveness of the developed system, a case of automobile generator is tested. The results show that the developed system can provide a "good" planning tool for an assembly planner within a reasonable computation time period.