• Journal of the Korean Institute of Telematics and Electronics
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• v.27 no.6
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• pp.944-953
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• 1990

This paper describes design and implementation of a real-time high-precision vision system for an automation of SMT(surface mounting technology ). Also, a part inspection algorithm which calculates the position and direction of SMD(surface mounted device) accurately and performs the ruling using those information are presented, and a parallel processing technique for implementing those algorithms is also described. For a real-time implementation of iage acquisition and processing, several hardware modules, namely, multi-functional A/D-D/A board, frame memory board are developed. Particularly, a PE (processing element) board which employs the DSP56001 DSP (digital signal processor) is developed for the purpose of concurrent processing of part inspection algorithms. A stand-alone vision system is built by integration of the developed hardware modules and related softwares.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.25 no.4
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• pp.54-60
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• 2002

In the Supply chain, The ATP(Available to Promise) function doesn't only give customers to conformation of delivery. It can be used by the core function with ATP rule that can reconcile supplies and demands on the supply chain. Therefore We can be acquire the conformation about on the due date of supplier by using the ATP function of management about real and concurrent access on the supply chain, also decide the affect about product availability due to forecasting or customer's orders through the ATP. In this paper, It consolidates the necessity on a ATP and analyzes data which is concerned of ATP. tinder the these environments, defines the ATP nile that can improve the customer value and data flow related the eCRM and builds on a algorithm.

• IEIE Transactions on Smart Processing and Computing
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• v.3 no.6
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• pp.397-403
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• 2014

A new video compression standard called High Efficiency Video Coding (HEVC) has recently been released onto the market. HEVC provides higher coding performance compared to previous standards, but at the cost of a significant increase in encoding complexity, particularly in motion estimation (ME). At the same time, the computing capabilities of Graphics Processing Units (GPUs) have become more powerful. This paper proposes a parallel integer-pel ME (IME) algorithm for HEVC on GPU using the Compute Unified Device Architecture (CUDA). In the proposed IME, concurrent parallel reduction (CPR) is introduced. CPR performs several parallel reduction (PR) operations concurrently to solve two problems in conventional PR; low thread utilization and high thread synchronization latency. The proposed encoder reduces the portion of IME in the encoder to almost zero with a 2.3% increase in bitrate. In terms of IME, the proposed IME is up to 172.6 times faster than the IME in the HEVC reference model.

• Journal of KIISE:Computer Systems and Theory
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• v.28 no.3
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• pp.155-160
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• 2001

본 논문은 영역별 근접 그래프 (geographic nearest neighbor graph)와 레인지 트리 (range tree)를 이용하여 평면 위의 n 개의 점에 대한 L$_{\infty}$ (L$_1$) 거리 (metric) 상의 디루니 삼각분할 (Delaunay triangulation)을 구축하는 방법을 소개한다. 이 방법은 L$_{\infty}$ (L$_1$) 거리 상에서 디루니 삼각분할에 있는 각 삼각형의 최소한 한 선분이 영역별 근접 그래프에 포함됨을 이용하여 레인지 트리 방법으로 디루니 삼각분할을 구축한다. 본 방법은 0(nlogn)의 순차계산 시간에 L$_{\infty}$ (L$_1$) 디루니 삼각분할을 구축하며, CREW-PRAM (Concurrent Read Exclusive Write Parallel Random Access Machine)에서 0(n)의 프로세서로 0(logn)의 병렬처리 시간에 L$_{\infty}$ (L$_1$) 디루니 삼각분할을 구축한다. 또한, 이 방법은 직선간의 교차점 계산 대신 거리비교를 하기 때문에 수치오차가 적고 구현이 용이하다.

• Proceedings of the Korean Information Science Society Conference
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• 2000.10a
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• pp.545-547
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• 2000

본 논문은 영역별 근접 그래프(geographic nearest neighbor graph)와 레인지 트리(range tree)를 이용하여 평면 위의 n 개의 점에 대한 L$\infty$(L1) 거리(metric) 상의 디루니 삼각분할(Delaunay triangulation)을 구축하는 방법을 소개한다. 이 방법은 L$\infty$(L1) 거리상에서 디루니 삼각분할에 있는 각 삼각형의 최소한 한 선분이 영역별 근접 그래프에 포함됨을 이용하여 레인지 트리 방법으로 디루니 삼각분할을 구축한다. 본 방법은 O(nlogn)의 순차계산 시간에 L$\infty$(L1) 디루니 삼각분할을 구축하며, CREW-PRAM (Concurrent Read Exclusive Write Programmable Random Access Machine)에서 O(n)의 프로세서로 O(logn)의 병렬처리 시간에 L$\infty$(L1) 디루니 삼각분할을 구축한다. 또한, 이 방법은 직선간의 교차점 계산 대신 거리비교를 하기 때문에 수치오차가 적고 구현이 용이하다.

• The Transactions of the Korea Information Processing Society
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• v.6 no.10
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• pp.2797-2808
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• 1999

Timing Constraint Petri Nets(TCPN) extend petri nets by adding timing constraints, it is provide a formal method for the modeling and analysis of real-time system. A real-time schedulability analysis decide that a set of concurrent processes will always meet its deadline. In this paper, we present TCPN model for real-time system include timing constraints and propose a schedulability analysis algorithm using them. Also, When the TCPN model is unscheduleable under the imposed timing constraints, we propose a recovery technique that will be scheduleable by the system specification modifying or timing constraints relaxing in the optimized time.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.19 no.39
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• pp.193-204
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• 1996

본 연구는 FMC(Flexible Manufacturing Cell)에 있어 상호 간섭이 없는 부품의 흐름을 제어하기 위한 교착제거방법(Deadlock Avoidance Method)에 대한 제안으로서, 이 방법이 주요한 장점은 첫째, FMC의 환경을 쉽게 적용시킬 수 있고 둘째, 공정상의 부품에 대한 dispatching 모듈이 협력하도록 설계되어 있다는 것이다. 교착제거방법은 두 개의 모듈로 구성되어 있는데 이는 순환발견알고리즘(A Cycle Detection Algorithm)과 원료주문 정책으로서, 특이할 만한 사항은 순환발견알고리즘을 채용하더라도 원료주문정책이 잘못될 수 있기 때문에 교착제거방법에 있어서 원료주문정책은 매우 중요하다는 것이다. 이를 위하여 교착전의 N-step 교착을 제거하고, 발견할 수 있는 교착제거방법과 N-step의 사전주무정책을 제시하였다.

• Journal of Ocean Engineering and Technology
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• v.37 no.3
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• pp.122-128
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• 2023

Autonomous berthing is a crucial technology for autonomous ships, requiring optimal trajectory planning to prevent collisions and minimize time and control efforts. This paper presents a two-phase, two-point boundary value problem (TPBVP) strategy for creating an optimal berthing trajectory for a twin-propeller, twin-rudder ship with autonomous berthing capabilities. The process is divided into two phases: the approach and the terminal. Tunnel thruster use is limited during the approach but fully employed during the terminal phase. This strategy permits concurrent optimization of the total trajectory duration, individual phase trajectories, and phase transition time. The efficacy of the proposed method is validated through two simulations. The first explores a scenario with phase transition, and the second generates a trajectory relying solely on the approach phase. The results affirm our algorithm's effectiveness in deciding transition necessity, identifying optimal transition timing, and optimizing the trajectory accordingly. The proposed two-phase TPBVP approach holds significant implications for advancements in autonomous ship navigation, enhancing safety and efficiency in berthing operations.

• The KIPS Transactions:PartA
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• v.9A no.2
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• pp.137-146
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• 2002

In VOD server, in order to guarantee playback of continuous media, such as video, without hiccups for multiusers, the server has to manage its buffer sophisticatedly by prefeching a part of the data into the buffer As the continuous media data buffered by one user can be used again by the others, the number of disk accesses is reduced and then the latency time far the users is also reduced. In this paper, we propose a new buffer management technique for continuous media in VOD server. Our basic algorithm partitions the buffer into groups and then a group of buffer which has the lowest utilization is chosen and partitioned again for a new user. The basic algorithm is extended for supporting multiple streams and clip data and for providing VCR functions. Our proposed technique is able to increase in the number of concurrent users as increasing the utilization of the buffer and to minimize the average waiting time for multiuser accesses as the bandwidth of storage is slowly reached to the limit. In the simulation study for comparing the performance of our technique with that of the existing techniques, we show that the average waiting time is reduced mere than 50% and the number of concurrent users increases by 1 ∼5% as compared with those of the exiting techniques.

• Proceedings of the Korean Operations and Management Science Society Conference
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• 2006.11a
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• pp.599-617
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• 2006

A network model and a Genetic Algorithm(GA) is proposed to solve the simultaneous estimation of the trip distribution and traffic assignment from traffic counts in the congested networks in a logit-based Stochastic User Equilibrium (SUE). The model is formulated as a problem of minimizing the non-linear objective functions with the linear constraints. In the model, the flow-conservation constraints of the network are utilized to restrict the solution space and to force the link flows meet the traffic counts. The objective of the model is to minimize the discrepancies between the link flows satisfying the constraints of flow-conservation, trip production from origin, trip attraction to destination and traffic counts at observed links and the link flows estimated through the traffic assignment using the path flow estimator in the legit-based SUE. In the proposed GA, a chromosome is defined as a vector representing a set of Origin-Destination Matrix (ODM), link flows and travel-cost coefficient. Each chromosome is evaluated from the corresponding discrepancy, and the population of the chromosome is evolved by the concurrent simplex crossover and random mutation. To maintain the feasibility of solutions, a bounded vector shipment is applied during the crossover and mutation.