• Journal of the Semiconductor & Display Technology
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• v.23 no.1
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• pp.65-70
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• 2024

Direct cache-to-cache transfer has been studied to reduce the latency and bandwidth consumption related to the shared data in multiprocessor system. Even though these studies lead to meaningful results, they assume that caches consist of SRAM. For example, if the system employs the non-volatile memory, the one of the most important parts to consider is to decrease the number of write operations. This paper proposes a hybrid write avoidance cache coherence protocol that considers the hybrid cache architecture. A new state is added to finely control what is stored in the non-volatile memory area, and experimental results showed that the number of writes was reduced by about 36% compared to the existing schemes.

• Journal of the Institute of Electronics and Information Engineers
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• v.52 no.4
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• pp.115-124
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• 2015

In this paper, the method which improves the performance of a serial decimal multiplier, and the method which operates multiple-digit simultaneously are proposed. The proposed serial decimal multiplier reduces the delay by removing encoding module that generates 2X, 4X multiples, and by generating partial product using shift operation. Also, this multiplier reduces the number of operations using multiple-digit operation. In order to estimate the performance of the proposed multiplier, we synthesized the proposed multiplier with design compiler with SMIC 110nm CMOS library. Synthesis results show that the area of the proposed serial decimal multiplier is increased by 4%, but the delay is reduced by 5% compared to existing serial decimal multiplier. In addition, the trade off between area and latency with respect to the number of concurrent operations in the proposed multiple-digit multiplier is confirmed.

• Journal of the military operations research society of Korea
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• v.3 no.1
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• pp.83-96
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• 1977

The combustion chamber and nozzle of an end burning, small spherical rocket is designed. A spherical external shape has a number of advantages such as fixed center-of-gravity and minimum aerodynamic precession torques during flight and a better mass distribution for gyro-stabilization as contrasted to a conventional ogive rocket shape. It is shown that the cross-sectional variation of the end burning solid propellant with length is an exponential geometry to provide a constant thrust-weight ratio of the rocket device during the propellant burning period, and that the factors which affect the attainment of the constant relationship of thrust to weight in the design are the initial propellant area, initial weight of the rocket and propellant density. The measurement of the transient thrust in the ground static test using black powder propellant supports the predicted results. A wind tunnel having a $30{\times}30{\times}75cm$ test section and Mach number 0.11 is constructed, and a simple balance-type device is designed for the measurement of the drag of a spinning sphere. The experimental results indicate that the. spinning has no effect on the magnitude of the drag up to the Reynolds number $3{\times}10^5$. Numerical computation of the flight trajectories for various launching angles is presented, and the gyro-stabilization of spinning sphere is discussed.

• Journal of KIISE:Databases
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• v.37 no.5
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• pp.238-249
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• 2010

Flash memory has been studied as a storage medium in order to improve the performance of the system using its high computing speed in the DBMS field where frequent data access is needed. The most difficulty using the flash memory is the performance degradation and the life span shortening of flash memory coming from inefficient in-place update. Log based approaches have been studied to solve inefficient in-place update problem in the DBMS where write operations occur in smaller size of data than page frequently. However the existing log based approaches suffer from the frequent merging operations, which are the principal cause of performance deterioration. Thus is because their fixed log area management can not guarantee a sufficient space for logs. In this paper, we propose non-fixed log area management technique that can minimize the occurrence of the merging operations by promising an enough space for logs. We also suggest the cost calculation model of the optimal log sector number minimizing the system operation cost in a block. In experiment, we show that our non-fixed log area management technique can have the improved performance compared to existing approaches.

• Proceedings of the Society of Korea Industrial and System Engineering Conference
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• 2002.05a
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• pp.379-386
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• 2002

As the value and relative importance of service industry boosts in modern society, to strengthen competitiveness companies starts to recognize the quality of service as a key component in their business operations. Furthermore, companies that apply the quality of services as their competitive method are concentrating more on the area of quality control. Nevertheless, the previous researches related to this area were more focused on the aspect of measure rather than the control. In this paper, each fractionated customer group in consideration of its characteristics is made in use of estimating the quality of service using the conjoint analysis. The principal variable selective method which a small number of variables is used to control a large number of variables is applied. Hotelling's $T^2$ control chart is applied to administer many relative variables of the quality of service because it is a Multi-item. If abnormal indications appear by adding new data, the method to find and improve variables using MYT decomposition is suggested to apply.

• The Mathematical Education
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• v.59 no.2
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• pp.167-183
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• 2020

This study is an analysis study on the number and operation area of middle school mathematics curriculum. This study is a literature analysis study that analyzes the historical transition process of number and operation area, and suggests the restructuring direction of mathematics learning contents for numbers and operation areas based on the results. In order to achieve this research purpose, the contents of the number and operation areas suggested from the 1st middle school mathematics curriculum to the 2015 revised middle school mathematics curriculum were considered. In addition, in this study, analysis of the mathematical learning contents of number and operation area was conducted. The details of the study are as follows. First, it was decided as a tertiary mathematics curriculum as a criterion for analysis. Second, a basic analysis framework was developed by subdividing the content of mathematics learning into content elements and terminology elements. Third, on the basis of the developed analysis framework, mathematics learning contents that are the core issues of number and operation area were extracted. Fourth, the extracted mathematics learning contents were compared with foreign curriculum. Finally, based on the analysis results, the direction of restructuring for the number and operation area of middle school was suggested. The results of this study are expected to be the basis for the development of a new curriculum.

• Korean Journal of Computational Design and Engineering
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• v.3 no.4
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• pp.236-242
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• 1998

This paper presents a development of computer aided cutting tool selection techniques for rough and finish turning operations. The developed system,. which is one of important activities for computer aided operation planning, firstly implements operation sequencing. Then, from relations of the size of machined area, recommended finishing allowance and maximum depth of cut, a main machining method is selected, a number of cut is calculated, cutting tools including toolholders and inserts are selected, and values for cutting parameters are determined. A cutting tool selection procedure is proposed for toolholders and inserts of ISO code in rough cutting, and some important parameters such as holder style, tool approach angle, tool function and its direction are described in detail. In order to demonstrate the validity of the system a case study is performed.

• Korean Management Science Review
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• v.4
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• pp.12-41
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• 1987

FMS has received a great deal of attention in the past two decades as a possible breakthrough for the new technologies in manufacturing. Some people say that the era of FMS has just begun. We have seen the potential benefits of FMS to the manufacturing industries. But it seems that FMS has generated a large number of problems to solve. The objective of this paper is to provide a groundwork for researches in the area of FMS by discussing the current status and prospect. The current status of installations and operations of FMS worldwide is reviewed. U.S.A., Japan, Western Europe, U.S.S.R. and Eastern Europe, and domestic status are discussed briefly. The current status of researches that are related to the FMS is also reviewed. Lastly, the prospect of hardware and software is discussed.

• Journal of the Korean Operations Research and Management Science Society
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• v.13 no.1
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• pp.39-50
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• 1988

The warehousing of inventories is an enormous expense to industries worldwide, and yet there are few available that can be used to design rack storage systems while considering overall system costs. The primary objective of this paper is the development of an overall ware hous storage system costs model to aid a warehous planner in the design of automated warehouse systems. A simulation model and statistical estimation procedures are used to determine the maximum inventory levels accumulated in the receiving, storage, and shipping areas. The overall cost model is developed to determine the required total land, the initial investment fund, the number of pieces of handling equipment, and the storage rack configuration for the main storage area. A numerical example is then presented to demonstrate the application of the overall system cost model developed in this paper.

• Proceedings of the Korean Operations and Management Science Society Conference
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• 1996.10a
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• pp.225-228
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• 1996

This paper proposes a design methodology for distributed databases connected by a LAN. Two primary objectives of the methodology are (i) to allocate data files and workload among heterogeneous servers and (ii) to determine the number of servers to satisfy the response time required for processing each transaction. The file and workload allocation decision is formulated as a nonlinear zero-one integer programming problem. This problem is proven to be NP-complete. A heuristic is developed to solve this problem effectively. A decision support system is implemented and an example is solved to illustrate the practical usefulness of the system.