• Journal of Korean Society of Transportation
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• v.18 no.4
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• pp.7-18
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• 2000

KS-SIGNAL, a traffic signal optimization model for coordinated arterials, is an optimization model using the mixed integer linear Programming that minimizes total delay on arterials by optimizing left-turn Phase sequences. However, the Previous version of KS-SIGNAL had a difficulty in reducing computation speed because the related variables and constraints multiply rapidly in accordance with the increase of intersections. This study is designed to propose a new model, improving optimizing computation speed in KS-SIGMAl, and evaluate it. This Paper Puts forth three kinds of methodological approaches as to achieve the above goals. At the first step to reduce run-time in the proposed model objective function and a few constraints are Partially modified, which replaces variable in related to queue clearance time with constant, by using thru-movements at upstream intersection and the length of red time at downstream intersection. The result shows that the run-time can be reduced up to 70% at this step. The second step to load the library in LINDO for Windows, in order to solve mixed integer linear programming. The result suggests that run-time can be reduced obviously up to 99% of the first step result. The third step is to add constraints in related to left-turn Phase sequences. The proposed methodological approach, not optimizing all kinds of left-turn sequences, is more reasonable than that of previous model , only in the view of reducing run-tim. In conclusion, run-time could be reduced up to 30% compared with the second results. This Proposed model was tested by several optimization scenarios. The results in this study reveals that signal timing plan in KS-SIGNAL is closer to PASSER-II (bandwidth maximizing model) rather than to TRANSYT-7F(delay minimizing model).

• KIPS Transactions on Computer and Communication Systems
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• v.7 no.1
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• pp.9-18
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• 2018

Enhancing performance of big data analytics in distributed environment has been issued because most of the big data related applications such as machine learning techniques and streaming services generally utilize distributed computing frameworks. Thus, optimizing performance of those applications at Spark has been actively researched. Since optimizing performance of the applications at distributed environment is challenging because it not only needs optimizing the applications themselves but also requires tuning of the distributed system configuration parameters. Although prior researches made a huge effort to improve execution performance, most of them only focused on one of three performance optimization aspect: application design, system tuning, hardware utilization. Thus, they couldn't handle an orchestration of those aspects. In this paper, we deeply analyze and model the application processing procedure of the Spark. Through the analyzed results, we propose performance optimization schemes for each step of the procedure: inner stage and outer stage. We also propose appropriate partitioning mechanism by analyzing relationship between partitioning parallelism and performance of the applications. We applied those three performance optimization schemes to WordCount, Pagerank, and Kmeans which are basic big data analytics and found nearly 50% performance improvement when all of those schemes are applied.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.9 no.1
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• pp.111-120
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• 2010

The policy which encourages people to use cars on the road has been based on the growth of economy in Korea. It has also caused the concentration and overcrowding in Seoul. That's because the increasing number of people possessing cars interconnects with the urban development. The transportation is a derived demand; so many scholars have recognized the importance of understanding the relationship between urban land use and transport. Considering such importance, this study theoretically compared the developed urban land use-transportation models each other and outlined the particular models briefly. Models were categorized by 2 types; optimizing model and predictive mode. Predictive model is also defined by static model, entropy based model, spatial-economic model, and activity model. After studying models, we investigated other major cities in America. This process is the pre-step for transport policy assessment. Through careful literature review, we can finally develop the integrated land-use transportation model in Seoul metropolitan area. In addition, we will be able to deal the changes of traffic demand pattern under U-Society. Consequently, the results of this study can be applied to ITS projects in the future.

• Tribology and Lubricants
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• v.2 no.2
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• pp.32-43
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• 1986

The mobility method is used for optimizing dynamically-loaded journal bearings. Connecting -rod bearings in both diesel and gasoline engines are optimized by parametric studies of bearing span and clearance. The inertia effect of the connecting-rod is also included in this study. Minimum film thickness, maximum film pressure, and friction loss are calculated to satisfy the design conditions in both engines.

• Proceedings of the Korean Society for Information Management Conference
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• 2002.08a
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• pp.241-246
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• 2002

전역적 질의확장 검색에서 단어간 공기기반 유사도를 사용할 경우에는 질의에 추가되는 용어에 부여하는 탐색가중치로 질의와의 유사도를 사용하는 것이 일반적이다. 그러나 과연 유사도가 탐색가중치로 최적인가는 의문의 여지가 있다. 추가용어와 질의 사이의 유사도가 가지는 특성을 살펴보고 고정가중치를 부여한 경우와 비교해보았다. 또한 실험집단이나 확장범위의 영향을 덜 받는 최적화된 추가용어 가중치를 찾기 위해 여러 가지 탐색가중치 공식을 실험하였다.

• Proceedings of the Korean Information Science Society Conference
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• 1998.10a
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• pp.759-761
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• 1998

90년대 중반 이후 고성능의 프로세서들은 성능 향상을 위해 명령어 수준의 병렬성을 이용하고 있다. 특히 실행화일의 호환성을 고려할 필요가 없는 마이크로컨트롤에서는 같은 하드웨어로 더 많은 함수유닛을 가질 수 있는 VLIW 구조가 널리 사용된다. 이러한 VLIW형의 마이크로컨트롤러에서는 병렬성을 추출하는 역할이 전적으로 소프트웨어에 있으므로 컴파일어가 성능향상에 매우 큰 영향을 미치게 된다. 본 논문에서는 마이크로컨트롤러의 구조와 그룹짓기 조건을 분석하고 선택 스케쥴링과 소프트웨어 파이프라이닝을 이용한 VLIW형 마이크로컨트롤러용 최적화 컴파일러를 구현하고 그 성능을 측정한다.

• Journal of Biosystems Engineering
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• v.8 no.2
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• pp.69-85
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• 1983

Nonlinear Goal Programming(NGP)이 Multiple Objective Decision Making(MODM) 문제(問題)를 적정화(適正化)할 수 있는 방법(方法)으로 소개(紹介)가 되었다. 그리고 6 가지의 벼 조제(調製) 및 저장시설(貯藏施設)을 분석(分析)한 후, NGP에 의(依)하여 적정시설설계(適正施設設計)를 하기 위하여 Model Systems를 개발(開發)하고 그에 의(依)하여 MODM의 수학적(數學的) 모형(模型)을 개발(開發)하였다.

• 제어로봇시스템학회:학술대회논문집
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• 1997.10a
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• pp.629-632
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• 1997

This paper presents the design method of controller which is combined Genetic Algorithms with the Generalized minimum variance self tuning controller. It is shown that the controllers adapts to changes in the system parameters with time delays and noises. The self tuning effect is achieved through the recursive least square algorithm at the parameter estimation stage and also through the Robbins-Monro algorithm at the stage of optimizing a polynomial parameters. The computer simulation results are presented to illustrate the procedure and to show the performance of the control system.

• 제어로봇시스템학회:학술대회논문집
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• 1997.10a
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• pp.1828-1831
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• 1997

this paper, to represent the robot motion approximately in space, delas with algorithm for position recognition of space robot, target and obstacle with vision system in 2-D. And also there are algorithms for precise distance-measuring and calibration usign laser displacement system, and for trajectory selection for optimizing moving to object, and for robot locomtion with air-thrust valve. And the software synthesizing of these algorithms hleps operator to realize the situation certainly and perform the job without any difficulty.

• Proceedings of the IEEK Conference
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• 2000.06d
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• pp.159-162
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• 2000

Selecting locally optimum thresholds, based on optimizing a criterion composed of the area variation rate and the compactness of the segmented shape, is presented. The method is shown to have the shape-resolving property in the subtraction image, so that overlapped objects may be resolved into bright and dark evidences characterizing each object. As an application a vehicle detection algorithm robust to the operating conditions could be realized by applying simple merging rules to the geometrically correlated bright and dark evidences obtained by this local thresholding.