• 정보처리학회논문지C
• /
• 제16C권3호
• /
• pp.383-392
• /
• 2009

차세대 네트워크(NGN)는 QoS가 지원되는 광 대역 전달 망에서 세션 및 비-세션 서비스를 지원하기 위한 패킷 기반의 융합 망이다. NGN에서 네트워크 사용자에 따라 차별화된 서비스를 제공하기 위해서는 QoS 기반 자원제어가 이루어져 한다. 본 논문에서는 세션 및 자원제어 지연을 최소화하기 위하여 NGN 자원제어 인터페이스에 병행형 제어 스킴을 정의하였다. 시뮬레이션을 통하여 기존 및 제안된 NGN 제어 스킴들의 제어지연과 완료율을 측정 및 분석하였다. 두 단계 자원 제어에서 도착율 120 까지는 병행형과 순차형의 완료율이 100%를 달성하였으며, 병행형의 제어지연이 순차형에 비하여 약 21.5% 개선되었음을 확인하였다.

• 산업경영시스템학회지
• /
• 제29권1호
• /
• pp.1-8
• /
• 2006

This paper proposes a real-time resource allocation algorithm for minimizing the completion time of overall workflow process. The jobs in a workflow process are interrelated through the precedence graph including Sequence, AND, OR and Loop control structure. A resource should be allocated for the processing of each job, and the required processing time of the job can be varied by the resource allocation decision. Each resource has several inherent restrictions such as the functional, geographical, positional and other operational characteristics. The algorithm suggested in this paper selects an effective resource for each job by considering the precedence constraint and the resource characteristics such as processing time and the inherent restrictions. To investigate the performance of the proposed algorithm, several numerical tests are performed for four different workflow graphs including standard, parallel and two series-parallel structures. In the tests, the solutions by the proposed algorithm are compared with random and optimal solutions which are obtained by a random selection rule and a full enumeration method respectively.

• 대한전자공학회:학술대회논문집
• /
• 대한전자공학회 2000년도 하계종합학술대회 논문집(3)
• /
• pp.97-100
• /
• 2000

As network resources have become faster and demands for multimedia service through network have increased, the demand for Media server system has increased. These kinds of media server solve their bottle neck problem of internal storage device by using parallel system which takes advantage of fast network resource. Many vendors have suggested each of their media server system to solve these problem radically, but most of them require major modification of infra component and additional drawback has added. For example, storage mechanism for specific media requires new file system which is totally different from traditional one, and algorithm for enhancing performance may not suit for traditional operating system environment. In this paper, we designed a parallel media server based on web interface of traditional system and implemented a program for media server. Implemented server system performs parallel processing through web interface without any modification of traditional system, and controls which is related to merging load by distributed data is charged only to client and control server and consequently load of storage server can be minimized. And also, data transfer protocol for streaming media includes Retransfer algorithm and client Admission control policy relevant to performance of whole system.

• 한국정보과학회논문지:소프트웨어및응용
• /
• 제37권8호
• /
• pp.647-652
• /
• 2010

Esterel이라는 절차형(imperative) 동기(synchronous) 언어로부터 회로를 합성(synthesis)할 때, 하나의 동기장치(synchronizer)가 한 클럭에 중복사용되는 문제(schizophrenic parallel synchronizer)가 발생할 수 있다. 기존 컴파일러는 동기장치가 중복사용될 경우 동기장치를 복제하여 이 문제를 해결하고 있다. 본 논문은 동기장치가 중복사용되더라도 회로상/기능상 문제가 없는 조건을 제시하고, 이를 기반으로 소스코드를 분석하여 복제해야만 하는 동기장치를 찾아주는 알고리즘을 제안한다. 이 알고리즘은 컴파일러가 중복사용되는 동기장치들 중에서 꼭 복제해야만 하는 것을 알 수 있게 해 주어, Esterel 프로그램을 좀 더 작은 회로로 합성할 수 있도록 한다.

• 제어로봇시스템학회:학술대회논문집
• /
• 제어로봇시스템학회 1996년도 한국자동제어학술회의논문집(국내학술편); 포항공과대학교, 포항; 24-26 Oct. 1996
• /
• pp.1241-1244
• /
• 1996

This paper present a performance evaluation method for Timed Place Petri Nets modeled by Live-and-Bounded Circuits (LB-circuits) through a bottom-up approach. The method can handle the case for the nets having common resources(CR). The target system is divided into the sub-systems by disconnecting the common Transition-Transition-Path(TTP) or Place-Place-Path (PPP) between sub-systems. The common PPP pattern is classified into Parallel Common Resource (PCR) and Sequential Common Resource (SCR) in detail for handling common resources. We evaluate the performance of each divided sub-system, and calculate the sub-systems affect on the performance of the whole system. The facts are generalized as a theorem. The developed theorem are applied into the performance evaluation of an automated assembly system shown in an example. All the results are verified by simulation.

• ETRI Journal
• /
• 제28권5호
• /
• pp.631-637
• /
• 2006

In this paper we study the optimization issues of ring networks employing novel parallel multi-granularity hierarchical optical add-drop multiplexers (OADMs). In particular, we attempt to minimize the number of control elements for the off-line case. We present an integer linear programming formulation to obtain the lower bound in optimization, and propose an efficient heuristic algorithm called global bandwidth resource assignment that is suitable for the design of large-scale OADM networks.

• 한국인터넷방송통신학회논문지
• /
• 제19권1호
• /
• pp.111-116
• /
• 2019

최근 GPU가 그래픽 처리뿐 아니라 다양한 분야의 병렬 처리로 그 영역을 넓혀가고 있다. 그러나, 현재 GPU는 워크로드의 다양성을 반영하기보다 간결한 제어 구조를 통한 개별 워크로드의 병렬성 극대화에 초점을 맞추고 있다. 본 논문은 워크로드 특성을 반영한 GPU 작업 배치를 위해 GPU에서 수행되는 워크로드의 자원 사용 특성을 컴퓨팅 바운드형, 메모리 바운드형, 실행종속 지연형으로 분류한 후, 각 분류에서 병목점이 되는 세부 자원을 규명한다. 예를 들어 컴퓨팅 바운드형의 경우 단정밀도 연산장치, 배정밀도 연산장치, 특수함수 연산장치 등 병목 자원이 무엇인지 분석한다. 본 논문의 분석 결과는 동일한 컴퓨팅 바운드형 워크로드라도 병목이 되는 세부 자원이 다를 경우 함께 배치하는 것이 성능 충돌을 일으키지 않는다는 점을 규명하여 GPU 작업배치의 효율화에 기여할 것으로 기대된다.

• Geomechanics and Engineering
• /
• 제20권6호
• /
• pp.517-525
• /
• 2020

The long-term stability of rock engineering is significantly affected by the time-dependent deformation behavior of rock, which is an important mechanical property of rock for engineering design. Although the hard rocks show small creep deformation, it cannot be ignored under high-stress condition during deep excavation. The inner mechanism of creep is complicated, therefore, it is necessary to investigate the relationship between microscopic creep mechanism and the macro creep behavior of rock. Microscopic numerical modeling of sandstone creep was performed in the investigation. A numerical sandstone sample was generated and Parallel Bond contact and Burger's contact model were assigned to the contacts between particles in DEM simulation. Sensitivity analysis of the microscopic creep parameters was conducted to explore how microscopic parameters affect the macroscopic creep deformation. The results show that the microscopic creep parameters have linear correlations with the corresponding macroscopic creep parameters, whereas the friction coefficient shows power function with peak strength and Young's modulus, respectively. Moreover, the microscopic parameters were calibrated. The creep modeling curve is in good agreement with the verification test result. Finally, the creep curves under one-step loading and multi-step loading were compared. This investigation can act as a helpful reference for modeling rock creep behavior from a microscopic mechanism perspective.

• 한국인터넷방송통신학회논문지
• /
• 제15권1호
• /
• pp.237-243
• /
• 2015

본 논문에서는 다중 모터 기반 피드백 제어 시스템에 대하여 캐스케이드 형태의 제어기를 고려하고 제한된 ADC(Analog to Digital Converter) 자원을 효과적으로 이용하기 위한 자원 할당 방법을 제안한다. 이 방법의 목적은 한정된 ADC 자원으로 모터 위치 측정값의 오차 및 d-q 축 전류 측정값의 오차를 최소화하는 것이다. 다중 모터 기반 피드백 제어 시스템에 대한 캐스케이드 제어 구조는 속도 제어기와 전류제어기로 구성되며, 이러한 구조가 각 모터에 병렬로 적용되어 각 모터의 회전 속도가 독립적으로 제어된다. 다중모터제어기는 추가되는 마이크로컨트롤러 없이 오직 하나의 컨트롤러에 구현된다. 다수의 AC 모터로 구성된 실험환경과 제안된 제어구조 및 ADC 할당방법을 이용함으로써 각 모터의 속도 및 토크가 주어진 속도 지령값을 정밀하게 추종함을 보인다.

• Journal of Communications and Networks
• /
• 제15권1호
• /
• pp.102-110
• /
• 2013

This paper considers a cooperative orthogonal frequency division multiple access (OFDMA)-based cognitive radio network where the primary system leases some of its subchannels to the secondary system for a fraction of time in exchange for the secondary users (SUs) assisting the transmission of primary users (PUs) as relays. Our aim is to determine the cooperation strategies among the primary and secondary systems so as to maximize the sum-rate of SUs while maintaining quality-of-service (QoS) requirements of PUs. We formulate a joint optimization problem of PU transmission mode selection, SU (or relay) selection, subcarrier assignment, power control, and time allocation. By applying dual method, this mixed integer programming problem is decomposed into parallel per-subcarrier subproblems, with each determining the cooperation strategy between one PU and one SU. We show that, on each leased subcarrier, the optimal strategy is to let a SU exclusively act as a relay or transmit for itself. This result is fundamentally different from the conventional spectrum leasing in single-channel systems where a SU must transmit a fraction of time for itself if it helps the PU's transmission. We then propose a subgradient-based algorithm to find the asymptotically optimal solution to the primal problem in polynomial time. Simulation results demonstrate that the proposed algorithm can significantly enhance the network performance.