• Journal of Information Processing Systems
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• 제3권1호
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• pp.26-32
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• 2007

Although the Java bytecode has numerous advantages, it also has certain shortcomings such as its slow execution speed and difficulty of analysis. In order to overcome such disadvantages, a bytecode analysis and optimization must be performed. The control flow of the bytecode should be analyzed; next, information is required regarding where the variables are defined and used to conduct a dataflow analysis and optimization. There may be cases where variables with an identical name contain different values at different locations during execution, according to the value assigned to a given variable in each location. Therefore, in order to statically determine the value and type, the variables must be separated according to allocation. In order to achieve this, variables can be expressed using a static single assignment form. After transformation into a static single assignment form, the type information of each node expressed by each variable and expression must be configured to perform a static analysis and optimization. Based on the basic type information, this paper proposes a method for finding the related equivalent nodes, setting nodes with strong connection components, and efficiently assigning each node type.

• 대한산업공학회지
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• 제35권2호
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• pp.150-159
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• 2009

The heterogeneous fleet vehicle routing problem(HVRP) is a variant of the classical vehicle routing problem in which customers are served by a heterogeneous fleet of vehicles with various capacities, fixed costs and variable costs. We propose a new conceptual HVRPCR(HVRP with customer restriction) model including additional customer restrictions in HVRP. In this paper, we develop hybrid particle swarm optimization(HPSO) algorithm with 2-opt and node exchange technique for HVRP. The solution representation is a n-dimensional particle for HVRP with N customers. The decoding method for this representation starts with the transformation of particle into a priority list of customer to enter route and limit of vehicle to serve each customer. The vehicle routes are then constructed based on the customer priority list and limit of vehicle to serve. The proposed algorithm is tested using 8 benchmark problems and it consistently produces high-quality solutions, including new best solutions. The numerical results show that the proposed algorithm is robust and efficient.

• International Journal of Computer Science & Network Security
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• 제22권4호
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• pp.261-273
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• 2022

Over the last decade, the scientific community has been actively developing technologies for automated software bug fixes called Automated Program Repair (APR). Several APR techniques have recently been proposed to effectively address multiple classroom programming errors. However, little attention has been paid to the advances in effective APR techniques for software bugs that are widely occurring during the software life cycle maintenance phase. To further enhance the concept of software testing and debugging, we recommend an optimized automated software repair approach based on hybrid technology (OAPR-HOML'1). The first contribution of the proposed OAPR-HOML'1 technique is to introduce an improved grasshopper optimization (IGO) algorithm for fault location identification in the given test projects. Then, we illustrate an opposition learning based artificial neural network (OL-ANN) technique to select AST node-level transformation schemas to create the sketches which provide automated program repair for those faulty projects. Finally, the OAPR-HOML'1 is evaluated using Defects4J benchmark and the performance is compared with the modern technologies number of bugs fixed, accuracy, precession, recall and F-measure.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제16권5호
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• pp.1708-1734
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• 2022

In the development of logistics system, the breakthrough of important technologies such as technology platform for logistics information management and control is the key content of the study. Based on Javascript and JQuery, the logistics system realizes real-time monitoring, collection of historical status data, statistical analysis and display, intelligent recommendation and other functions. In order to strengthen the cooperation of warehouse storage, enhance the utilization rate of resources, and achieve the purpose of real-time and visual supervision of transportation equipment and cargo tracking, this paper studies the VNF dynamic deployment and SFC routing problem in the network load change scenario based on the logistics system. The BIP model is used to model the VNF dynamic deployment and routing problem. The optimization objective is to minimize the total cost overhead generated by each SFCR. Furthermore, the application of the SFC mapping algorithm in the routing topology solving problem is proposed. Based on the concept of relative cost and the idea of topology transformation, the SFC-map algorithm can efficiently complete the dynamic deployment of VNF and the routing calculation of SFC by using multi-layer graph. In the simulation platform based on the logistics system, the proposed algorithm is compared with VNF-DRA algorithm and Provision Traffic algorithm in the network receiving rate, throughput, path end-to-end delay, deployment number, running time and utilization rate. According to the test results, it is verified that the test results of the optimization algorithm in this paper are obviously improved compared with the comparison method, and it has higher practical application and promotion value.

• 한국정보과학회논문지:컴퓨팅의 실제 및 레터
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• 제15권1호
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• pp.62-66
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• 2009

많은 컴파일러는 속도를 높이기 위해서 최적화를 수행한다. 최적화의 결과로 프로그램의 구문이 변경된다. 단일 스레드 소프트웨어에서는 변경된 구문이 영향을 받지 않지만 멀티스레드 소프트웨어에서는 변경된 구문 때문에 예상하지 못한 실행 결과가 발생할 수 있다. 멀티 스레드자바 소프트웨어는 스레드들 간에 메모리를 통한 상호작용을 자바 메모리 모델을 통해서 명세 한다. 자바 메모리 모델은 자바언어의 표준 메모리 모델이다. 하지만 현재까지 나와 있는 어떠한 자바 모델 체킹 도구도 자바 메모리 모델을 지원하지 않는다. 본 논문에서는 자바 메모리 모델을 지원하는 모델 체킹 도구를 개발하기 위해서 자바 메모리 모델을 지원하는 시물레이터를 많은 모델 체킹 도구에서 사용되는 SMT 기반으로 구현했다. SMT 기반 메모리 모델 시뮬레이터는 기존의 메모리 모델 시뮬레이터에서 몇분이 걸리는 계산 결과를 1초 이내에 계산하였다. 또한 이를 통해 기존 소프트웨어 모델 체킹에서 표현할 수 없는 실행 결과를 빠르게 표현할 수 있다.

• 한국도로학회논문집
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• 제17권1호
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• pp.91-98
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• 2015

PURPOSES : Although signalized intersections have been considered the best way to control traffic volume in urban areas for several decades, roundabouts are currently being discussed as an alternative way to control traffic volume, especially when traffic is light. Because a roundabout's efficiency depends on the load geometry as well as the traffic volume, design guidelines for roundabouts are recommended only if the incoming traffic volume is very low. It is rare to substitute a roundabout for an existing signalized intersection in urban areas. This study aims to estimate the benefits from the transformation of an existing signalized intersection into a roundabout in an urban area. When there is a more moderate volume of traffic, roundabouts can be effectively used by optimizing signals located at an approaching roadway. METHODS : The methodologies of this paper are as follows: First, a signalized intersection was analyzed to determine the traffic characteristics. Second, the signalized intersection was transformed into a roundabout using VISSIM microscopic traffic simulation. Then, we estimated and analyzed the effects and the performance of the roundabout. In addition, we adjusted a method to improve the benefits of the transformation via the optimization of signals located at an approaching road to control the incoming traffic volume. RESULTS : The results of this research are as follows: The signal-optimized roundabout improved delays compared with the signalized intersection during the morning peak hour, non-peak hour, and evening peak hour by 1.78%, 12.45%, and 12.72%, respectively. CONCLUSIONS : According to the simulation results of each scenarios, the signal-optimized roundabout had less delay time than the signalized intersection. If optimized signal control algorithms are installed in roundabouts in the future, this will lead to more efficient traffic management.

• 디지털콘텐츠학회 논문지
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• 제19권1호
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• pp.1-10
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• 2018

본 연구는 디지털 마케팅의 구성요인과 앞으로의 흐름을 예측하기 위해 계층적 분석 방법(AHP)을 활용하여 디지털 마케팅 구성 요인간의 상대적 중요도를 도출하고 광고 부문 전문가와 비광고 부문 전문가의 의견을 비교 분석하였다. 연구 결과, 디지털 마케팅 상위요인들의 상대적 중요도는 결합(0.260), 전환(0.259), 최적화(0.243), 기반 기술(0.238)의 순으로 나타났으며 하위요인들의 상대적 중요도는 인공지능과 머신러닝(0.086), 빅데이터(0.085), 콘텐츠 큐레이션(0.060) 순으로 나타났다. 또한, 광고 부문 전문가들은 결합과 최적화의 상대적 중요도가 높은데 반해 비광고 부문 전문가는 전환과 기반기술로 나타나 직무 특성 별 상대적 중요도가 다르다는 것을 확인할 수 있었다. 본 연구는 디지털 마케팅의 전체적인 구성 요인과 중요도를 통해 향후 디지털 마케팅 전략을 수립하는데 유용한 시사점을 제공할 수 있다.

• 정보과학회 논문지
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• 제43권1호
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• pp.126-134
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• 2016

OLED 디스플레이는 빠른 응답속도, 전력 효율성 등 여러 장점 때문에 점차 사용이 증가하고 있는 추세이다. 뛰어난 전력 효율성에도 불구하고 메신저, 게임 등의 사용자와의 상호작용 기반의 어플리케이션 사용의 증가로 OLED에 의한 전력 소모 비중이 여전히 크게 나타나고 있다. OLED에서는 출력하는 영상에 따라 소모 전력이 크게 달라지기 때문에 저전력 색 변환 기법이 대표적인 전력 절감 기법이다. 기존의 저전력 색 변환 기법들은 색 변환 시 인간 시각 시스템의 만족에 대한 엄밀한 연구가 없으며, 시각 만족도와 소모 전력을 동시에 최적으로 고려하는 연구가 부재했다. 본 연구에서는 기존 기법들의 문제점을 보완한 새로운 저전력 색변환 기법을 제안한다. 실험 결과를 통해서 제안 기법이 기존 기법보다 시각 만족도 측면에서 더 인간 시각 시스템을 만족하며 또 전력절감 측면에서도 색 변환거리에 따라 기존 기법보다 평균 13.4% 및 22.4% 향상된 전력 절감이 가능한 것으로 나타났다.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제12권6호
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• pp.2595-2618
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• 2018

In this paper, we investigate secure communication with the presence of multiple eavesdroppers (Eves) in a two-tier downlink dense heterogeneous network, wherein there is a macrocell base station (MBS) and multiple femtocell base stations (FBSs). Each base station (BS) has multiple users. And Eves attempt to wiretap a macrocell user (MU). To keep Eves ignorant of the confidential message, we propose a physical-layer security scheme based on cross-layer cooperation to exploit interference in the considered network. Under the constraints on the quality of service (QoS) of other legitimate users and transmit power, the secrecy rate of system can be maximized through jointly optimizing the beamforming vectors of MBS and cooperative FBSs. We explore the problem of maximizing secrecy rate in both non-colluding and colluding Eves scenarios, respectively. Firstly, in non-colluding Eves scenario, we approximate the original non-convex problem into a few semi-definite programs (SDPs) by employing the semi-definite relaxation (SDR) technique and conservative convex approximation under perfect channel state information (CSI) case. Furthermore, we extend the frame to imperfect CSI case and use the Lagrangian dual theory to cope with uncertain constraints on CSI. Secondly, in colluding Eves scenario, we transform the original problem into a two-tier optimization problem equivalently. Among them, the outer layer problem is a single variable optimization problem and can be solved by one-dimensional linear search. While the inner-layer optimization problem is transformed into a convex SDP problem with SDR technique and Charnes-Cooper transformation. In the perfect CSI case of both non-colluding and colluding Eves scenarios, we prove that the relaxation of SDR is tight and analyze the complexity of proposed algorithms. Finally, simulation results validate the effectiveness and robustness of proposed scheme.

• 한국콘텐츠학회논문지
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• 제10권2호
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• pp.89-98
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• 2010

엔터프라이즈 시스템은 점점 복잡해지고 대형화되고 있다. 시대적 흐름에 따라 재사용에 초점을 맞춘 객체지향 프로그래밍 방법으로 시스템을 개발하고 있다. 하지만, 객체지향 방법에서는 core class에 중복되는 코드가 삽입되기 때문에, 생산성 저하, 새로운 요구사항을 적용하기 어려운 문제가 발생한다. 이 단점을 해결하기 위하여, 메타데이터와 크로스커팅 개념을 적용하는 위빙 메카니즘을 제안한다. 클래스 최적화와 다른 언어사이의 통합을 위하여 다음의 방법을 사용한다. 리플렉션을 이용한 메타데이타 생성, 추상구조트리로의 변환, 그리고 XML로 명세된 크로스커팅 정보를 통한 매핑을 이용한다. 제안하는 방법을 이용하여, 기능의 분산과 코드의 혼란을 해결함으로서 클래스를 최적화 할 수 있다.