• 인터넷정보학회논문지
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• 제2권1호
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• pp.23-30
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• 2001

ILP 프로세서는 고성능을 유지하기 위해 정확한 분기예상 방법을 요구한다. Two-Level 분기예상 방법은 높은 분기예상 정확성을 갖는 것으로 알려져 있다. 그러나, 한 분기 명령이 다른 분기 명령에 의해 갱신된 PHT 엔트리를 사용할 때 간섭이 발생하며, 간섭 중 부정적 간섭은 잘못된 예상(misprediction)을 유발하여 성능에 부정적 영향을 주게 된다. Agree분기예상 방법에서는 BTB에 bias 비트를 추가하여 부정적 간섭을 긍정적 간섭으로 변환하여 예상 정확도를 높였으나, bios 비트를 잘못 설정하는 경우에는 오히려 부정적 간섭이 증가하게 된다. 본 논문에서는 이러한 부정적 간섭을 감소시키는 새로운 동적 분기예상 방법을 제안한다. 제안한 분기예상 방법은 수행시간에 bias 비트를 동적으로 변경시키기 위해 BTB의 엔트리에 hit 비트를 추가하였다. 그 결과 부정적 간섭을 효과적으로 감소시켜 예상 정확도를 향상시켰다. 제안된 방법의 효율성을 보여주기 위해, SPEC92int 벤치마크를 사용하여 성능을 평가한 결과, 제안된 방법이 기존의 방법보다 성능이 우수함을 확인하였다.

• 한국정보과학회논문지:시스템및이론
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• 제26권9호
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• pp.1158-1165
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• 1999

조건부 분기 명령어(conditional branch instruction)의 잘못된 분기 예측(branch misprediction)은 프로세서의 성능 향상에 심각한 장애 요인이 되고 있다. 특히 시분할(time-sharing) 시스템과 같이 문맥 교환(context switch)이 발생하는 멀티프로그래밍 환경(multiprogramming environment)에서는 더욱 낮은 분기 예측 정확성(branch prediction accuracy)을 보인다. 본 논문에서는 문맥 교환이 발생하는 멀티프로그래밍 환경에서 높은 분기 예측 정확성을 보이는 중첩 분기 예측표 교환(Overlapped Predictor Table Switch, OPTS) 기법을 소개한다. 분기 예측표(predictor table)를 분할하여 각각의 프로세스(process)에 할당하는 OPTS 기법은 문맥 교환의 영향을 최소화함으로써 높은 분기 예측 정확성을 유지하는 분기 예측 방법이다.Abstract There is wide agreement that one of the most important impediments to the performance of current and future pipelined superscalar processors is the presence of conditional branches in the instruction stream. Accurate branch prediction is required to overcome this performance limitation. Many branch predictors have been proposed to help to alleviate this problem, including the two-level adaptive branch predictor, and more recently, hybrid branch predictor. In a less idealized environment, such as a time-sharing system, code of interest involves context switches. Context switches, even at fairly large intervals, can seriously degrade the performance of many of the most accurate branch prediction schemes. In this study, we measure the effect of context switch on the branch prediction accuracy in various situation and show the feasibility of our new mechanism, OPTS(Overlapped Predictor Table Switch), which save and restore branch history table at every context switch.

• 전기학회논문지
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• 제56권2호
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• pp.396-406
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• 2007

In this paper, we proposed development of improved model reduction and design of hierarchical controller using reduction model. The model reduction is considered that it is the transient response and the steady-state response through the use of nyquist curve. The hierarchical controller selected tuning of PID controller to ensure specified gain and phase margin and hybrid smith-predictor fuzzy controller using reduction model. Simulation examples are given to show the better performance of the proposed method than conventional methods.

• 한국경영과학회지
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• 제27권3호
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• pp.1-19
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• 2002

Recently, increasing attention has been paid to building a successful software process in Information System(IS) implementation. This study establishes software process model as a key predictor of organizational performance. We propose a theoretical framework for capability maturity model derived from the Software Engineering Institute(SEI). This paper identify the process-related variables, financial performance and non-financial performance from the relevant literature and clarify the concept of software process by distinguishing between its component and determinants. We then examine the impact of software process on organizational performance. Hypotheses on software process were tested for 36 enterprises including 118 organizational units. Results indicate that software process capability may serve as a key predictor of organizational performance. Software process maturity found to be positively influenced on the financial and non-financial performance, while investment of information technology as a mediating variable not significantly affected to the performance.

• 한국정보통신학회논문지
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• 제16권12호
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• pp.2725-2730
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• 2012

본 논문에서는 H.264/AVC 인코더의 성능 향상을 위해 다중 참조 프레임 기법과 묵시적 가중 예측 기법을 이용하고 낮은 외부 메모리 접근율을 위해 이전 참조 프레임 데이터를 재사용하는 인터 예측기 하드웨어 구조를 제안한다. 참조 소프트웨어JM16.0과 비교하여 참조 프레임 접근율이 약 24%만큼 감소하고 참조 영역 메모리가 약 46%만큼 감소하였다. 통합 구조는 Verilog HDL로 설계되고 Magnachip 0.18um공정으로 합성한 결과 게이트 수는 약 2,061k 이고 91Mhz로 동작한다.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1989년도 하계종합학술대회 논문집
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• pp.84-88
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• 1989

Recently electronic control of engine is used to satisfy exhaust gas restriction and to increase fuel economical efficiency and acceleration. In this paper, Smith-predictor method is applied to increase control performance for A/F command and disturbance. A/F control performance is simulated by A/F command and disturbance of Chevolet 5.7 liter engine and Toyota 4A-ELU engine. This method can be applied to A/F controller so that lion accurate and rapid A/F control is possible.

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 1999년도 하계종합학술대회 논문집
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• pp.1041-1044
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• 1999

In This paper, we investigated the single step prediction for output responses of chaotic system with multi Input multi output using chaotic neural networks. Since the systems with chaotic characteristics are coupled between internal parameters, the chaotic neural networks is very suitable for output response prediction of chaotic system. To evaluate the performance of the proposed neural network predictor, we adopt for Lorenz attractor with chaotic responses and compare the results with recurrent neural networks. The results demonstrated superior performance on convergence and computation time than the predictor using recurrent neural networks. And we could also see good predictive capability of chaotic neural network predictor.

• 한국시뮬레이션학회논문지
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• 제8권3호
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• pp.17-28
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• 1999

Recently studies have shown that conditional branches can be accurately predicted by recording the path leading up to the branch. But path predictors are more complex and uncompatible with existing pattern branch predictors. In order to solve these problems, we propose a simple path branch predictor(SPBP) that hashes together two most recent branch instruction addresses. In addition, we propose a pattern/path hybrid branch predictor composed of the SPBP and existing pattern branch predictors. Through the trace-driven simulation of six benchmark programs, the performance improvement by the proposed pattern/path hybrid branch prediction is analysed and validated. The proposed predictor can improve the prediction accuracy from 94.21% to 95.03%.

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 2002년도 하계종합학술대회 논문집(2)
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• pp.129-132
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• 2002

AE64000 is the 64-bit high-performance microprocessor that ADC Co. Ltd. is developing for an embedded environment. It has a 5-stage pipeline and uses Havard architecture with a separated instruction and data caches. It also provides SIMD-like DSP and FP operation by enabling the 8/16/32/64-bit MAC operation on 64-bit registers. AE64000 processor implements the EISC ISA and uses the instruction folding mechanism (Instruction Folding Unit) that effectively deals with LERI instruction in EISC ISA. But this unit makes branch prediction behavior difficult. In this paper, we designs a branch predictor optimized for AE64000 Pipeline and develops a AES4000 simulator that has cycle-level precision to validate the performance of the designed branch predictor. We makes TAC(Target address cache) and BPT(branch prediction table) seperated for effective branch prediction and uses the BPT(removed indexed) that has no address tags.

• 한국HCI학회:학술대회논문집
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• 한국HCI학회 2008년도 학술대회 2부
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• pp.64-70
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• 2008

Computer Assisted Learning (CAL) is quite different from in many aspects. CAL provides individualistic learning environment and facilitates autonomy of the learner. Thus the learners who uses CAL program has more sense of control and engages in more strategic learning than conventional learning environment. In this experiment, we used KORI (KORea university intelligent agent) which is a new type of ITS adopting TA (Teachable Agent) that fosters learning by teaching, So, we investigated the critical motivational factor that have influences in CAL learning and the effects of reward in CAL are another area of our interest. Thus, we divided two conditions that presence of reward and absence of reward. The 174 elementary school students(5th) were participated and they are randomly assigned the one of the reward conditions. Before entering the experimental instruction, all participants measured about metacognition, self-efficacy and goal orientation questionnaire as independent variables. Then, Participants were instructed of method of using KORI program and asked to study for ten days with KORI program at least 20 minutes everyday in their home, about 10 days. After 10 days, they were rated interest and comprehension. Regression results suggest that regardless of the presence of reward, metacognition is a positive predictor in interestingness. It indicate that metacognitive skills are required in CAL learning situation irrespective of reward. But on comprehension in the absence of reward, only self- efficacy appeared to be a positive predictor. In the presence of reward, performance goal orientation showed as a negative predictor of comprehension, whereas self-efficacy was a positive predictor. This result suggest that presence of reward especially interferes learning process of performance goal orientation in CAL learning situation. It could be interpreted that reward interferes the learning process of performance goal orientation by debilitating intrinsic motivation.