• Transactions of the Korean Society of Mechanical Engineers A
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• v.34 no.8
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• pp.971-980
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• 2010

In this paper, we present a navigation control algorithm for mobile robots that move in environments having static and moving obstacles. The algorithm includes a global and a local path-planning algorithm that uses $D^*$ search algorithm, a fuzzy logic for determining the immediate level of danger due to collision, and a fuzzy logic for evaluating the required wheel velocities of the mobile robot. To apply the $D^*$ search algorithm, the two-dimensional space that the robot moves in is decomposed into small rectangular cells. The algorithm is verified by performing simulations using the Python programming language as well as by using the dynamic equations for a two-wheeled mobile robot. The simulation results show that the algorithm can be used to move the robot successfully to reach the goal position, while avoiding moving and unknown static obstacles.

• Journal of the Korean Institute of Telematics and Electronics C
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• v.36C no.4
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• pp.31-43
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• 1999

The main goal of this paper is to design a high performance SVP(Stack based Video Processor) for network applications. The SVP is a comprehensive scheme; 'better' in the sense that it is an optimal selection of previously proposed enhancements of a stack machine and a video processor. This can process effectively object-based video data using a S-RISC(Stack-based Reduced Instruction Set Computer) with a semi -general-purpose architecture having a stack buffer for OOP(Object-Oriented Programming) with many small procedures at running programs. And it includes a vector processor that can improve the MPEG coding speed. The vector processor in the SVP can execute advanced mode motion compensation, motion prediction by half pixel and SA-DCT(Shape Adaptive-Discrete Cosine Transform) of MPEG-4. Absolutors and halfers in the vector processor make this architecture extensive to a encoder. We also designed a VLSI stack-oriented video processor using the proposed architecture of stack-oriented video decoding. It was designed with O.5$\mu\textrm{m}$ 3LM standard-cell technology, and has 110K logic gates and 12 Kbits SRAM internal buffer. The operating frequency is 50MHz. This executes algorithms of video decoding for QCIF 15fps(frame per second), maximum rate of VLBV(Very Low Bitrate Video) in MPEG-4.

• The Journal of Korean Institute for Practical Engineering Education
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• v.4 no.2
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• pp.38-45
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• 2012

Building a game has been used as effective and attractive way of teaching computer science. Building a usable Multi-player Game is requires important aspects of technology, teamwork and software engineering principles. The whole class was structured in to several teams and students needed to join one or two teams. Each team presented their progress, discussed future milestones and troubleshoots, updated documents for clearer communication and utilized SVN(Subversion) throughout the semester. Unlike usual class setting, all students worked collaboratively together like one company to achieve the goal. In one semester, students started from concept design and completed a working Multiplayer Online Game called "deBugger" (Fall 2009), and "World of Balance" (Fall 2011), while learning game design, 3D graphics, Game Engine, Server-client architecture, Game Protocol, network programming, database, Software Engineering principles, and large application development as a team project.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.8 no.3
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• pp.541-548
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• 2007

The workflow, one of core features for modern business operation, models common elements and their relationships in business processes. The research is focused on how to adapt the workflow model to the healthcare examination which becomes popular these days. Especially, we intend to have fully automated process for healthcare examination by providing customers with PDA with RFTD chip. In order to realize this goal, this paper proposes the design of software architectures the class structures, and the definition of messages used for the system interactions. In other word, the paper shows the analysis of healthcare application in terms of service scenario and the design of workflow engine ant ubiquitous healthcare application under the Object-Oriented programming environment. the The result of the study may also enable the unmanned healthcare examination as well as ubiquitous based healcare examination sooner or later.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.11 no.1
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• pp.39-60
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• 2017

In the Cloud, for the scheduling of parallel jobs, there are many tasks in a job and those tasks are executed concurrently on different VMs (Visual machines), where each task of the job will be executed synchronously. The goal of scheduling is to reduce the execution time and to keep the fairness between jobs to prevent some jobs from waiting more time than others. We propose a Cloud model which has multiple Clouds, and under this model, jobs are in different lists according to the waiting time of the jobs and every job has different parallelism. At the same time, a new method-ZOMT (the scheduling parallel tasks based on ZERO-ONE scheduling with multiple targets) is proposed to solve the problem of scheduling parallel jobs in the Cloud. Simulations of ZOMT, AFCFS (Adapted First Come First Served), LJFS (Largest Job First Served) and Fair are executed to test the performance of those methods. Metrics about the waiting time, and response time are used to test the performance of ZOMT. The simulation results have shown that ZOMT not only reduces waiting time and response time, but also provides fairness to jobs.

• Journal of KIISE:Software and Applications
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• v.30 no.1_2
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• pp.73-80
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• 2003

The Java programming language is designed for developing effective applications in a heterogeneous network environment. Major problem in Java is its performance. many attractive features of Java make the development of software easy, but also make it expensive to support ; applications written in Java are often much slower than their counterparts written in C or C++. To use Java`s attractive features without the performance penalty, sophisticated optimizations and runtime systems are required. Optimising Java bytecode has several advantages. First, the bytecode is independent of any compiler that is used to generate it. Second, the bytecode optimization can be performed as a pre=pass to Just-In-Time(JIT) compilation. Many attractive features of Java make the development of software easy, but also make it expensive to support. The goal of this work is to develop automatic construction of code optimizer for Java bytecode. We`ve designed and implemented a Bytecode Optimizer that performs the peephole optimization, bytecode-specific optimization, and method-inlining techniques. Using the Classfile optimizer, we see up to 9% improvement in speed and about 20% size reduction in Java class files, when compared to average code using the interpreter alone.

• Journal of the Korean Geographical Society
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• v.46 no.6
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• pp.724-737
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• 2011

The goal of solving a contiguous land acquisition problem is to find an optimal cluster of land parcels so that one can move from an acquired parcel to another without leaving the cluster. In many urban and regional planning applications, criteria such as acquisition cost and compactness of acquired parcels are important. Recent research has demonstrated that spatial contiguity can be formulated in a mixed integer programming framework. Spatial compactness, however, is typically formulated in an approximate manner using parameters such as external border length or other shape indices of acquired land parcels. This paper first develops an alternative measure of spatial compactness utilizing the characteristics of the internal structure of a contiguous set of land parcels and then incorporates this new measure into a mixed integer program of contiguous land acquisition problems. A set of computational experiments are designed to demonstrate the use of our model in a land acquisition context.

• Journal of Digital Convergence
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• v.11 no.7
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• pp.165-171
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• 2013

Coding patterns that appeared frequently in the source code is a typical piece of code. The functionality that difficult to modularize, such as logging or synchronization processing, and the useful sentences in programming is extracted in software as codding pattern. Large-scale software could not be analyzed fully because the number of coding pattern that can be manually investigated is limited. In this paper, the characteristics of coding patterns perform the evaluation. The goal is to extract for codding-pattern to analyzed by developer. We was selected 6 indicators and performed analysis of 4 open-source. Matrix relations between the values and characteristics of the actual pattern analysis, pattern instances, the width of the distribution of instances, the pattern repeating structure of the elements included in the rates should be analyzed for patterns and indicators that help in choosing was confirmed.

• KIPS Transactions on Computer and Communication Systems
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• v.4 no.12
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• pp.391-398
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• 2015

This paper devises a performance improvement and evaluation process of circuit minimization algorithms for mentorship education of distinguished informatics gifted secondary students. In the process, students learn that there are several alternative equivalent circuits for a target function and recognize the necessity for formalized circuit minimization methods. Firstly, they come at the concept of circuit minimization principle from Karnaugh Map which is a manual methodology. Secondly, they explore Quine-McCluskey algorithm which is a computational methodology. Quine-McCluskey algorithm's time complexity is high because it uses set operations. To improve the performance of Quine-McCluskey algorithm, we encourage them to adopt a bit-wise data structure instead of integer array for sets. They will eventually see that the performance achievement is about 36%. The ultimate goal of the process is to enlarge gifted students' interest and integrated knowledge about computer science encompassing electronic switches, logic gates, logic circuits, programming languages, data structures and algorithms.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2008.03a
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• pp.330-339
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• 2008

Ground-based interceptors(GBI) comprise a major element of the strategic defense against hostile targets like Intercontinental Ballistic Missiles(ICBM) and reentry vehicles(RV) dispersed from them. An optimum design of the subsystems is required to increase the performance and reliability of these GBI. Propulsion subsystem design and optimization is the motivation for this effort. This paper describes an effort in which an entire GBI missile system, including a multi-stage solid rocket booster, is considered simultaneously in a Genetic Algorithm(GA) performance optimization process. Single goal, constrained optimization is performed. For specified payload and miss distance, time of flight, the most important component in the optimization process is the booster, for its takeoff weight, time of flight, or a combination of the two. The GBI is assumed to be a multistage missile that uses target location data provided by two ground based RF radar sensors and two low earth orbit(LEO) IR sensors. 3Dimensional model is developed for a multistage target with a boost phase acceleration profile that depends on total mass, propellant mass and the specific impulse in the gravity field. The monostatic radar cross section (RCS) data of a three stage ICBM is used. For preliminary design, GBI is assumed to have a fixed initial position from the target launch point and zero launch delay. GBI carries the Kill Vehicle(KV) to an optimal position in space to allow it to complete the intercept. The objective is to design and optimize the propulsion system for the GBI that will fulfill mission requirements and objectives. The KV weight and volume requirements are specified in the problem definition before the optimization is computed. We have considered only continuous design variables, while considering discrete variables as input. Though the number of stages should also be one of the design variables, however, in this paper it is fixed as three. The elite solution from GA is passed on to(Sequential Quadratic Programming) SQP as near optimal guess. The SQP then performs local convergence to identify the minimum mass of the GBI. The performance of the three staged GBI is validated using a ballistic missile intercept scenario modeled in Matlab/SIMULINK.