• Journal of the Korean School Mathematics Society
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• v.13 no.3
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• pp.483-498
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• 2010

The purpose of this paper is to investigate the dispositions of university students' understanding and reasoning about rational number concept. For this, we surveyed for the subject groups of prospective math teachers(33), engineering major students(35), American engineering and science major students(28). The questionnaire consists of four problems related to understanding of rational number concept and three problems related to rational number operation reasoning. We asked multi-answers for the front four problem and the order of favorite algorithms for the back three problems. As a result, we found that university students don't understand exactly the facets of rational number and prefer the mechanic approaches rather than conceptual one. Furthermore, they reasoned illogically in many situations related to fraction, ratio, proportion, rational number and don't recognize exactly the connection between them, and confuse about rational number concept.

• JSTS:Journal of Semiconductor Technology and Science
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• v.12 no.4
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• pp.418-425
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• 2012

In this paper, efficient implementation of error correction code (ECC) processing circuits based on single error correction and double error detection (SEC-DED) code with check bit pre-computation is proposed for memories. During the write operation of memory, check bit pre-computation eliminates the overall bits computation required to detect a double error, thereby reducing the complexity of the ECC processing circuits. In order to implement the ECC processing circuits using the check bit pre-computation more efficiently, the proper SEC-DED codes are proposed. The H-matrix of the proposed SEC-DED code is the same as that of the odd-weight-column code during the write operation and is designed by replacing 0's with 1's at the last row of the H-matrix of the odd-weight-column code during the read operation. When compared with a conventional implementation utilizing the odd-weight- column code, the implementation based on the proposed SEC-DED code with check bit pre-computation achieves reductions in the number of gates, latency, and power consumption of the ECC processing circuits by up to 9.3%, 18.4%, and 14.1% for 64 data bits in a word.

• Proceedings of the KIPE Conference
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• 2012.11a
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• pp.217-218
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• 2012

A load motor used for warship or submarine is with limited volume and weight, also specific environmental tests like impact, vibration, noise, temperature and EMC/EMI have to be satisfied. Induction motors, synchronous motors, BLDC motor and etc, are used depending on the purpose of using military equipment. Induction Motors are used for a number of military equipment more commonly due to the robust structure and simple maintenance. Domestic and foreign warships have a wide range of voltages as the DC voltage sources with battery are mainly used for them. The ${\Delta}-connection$ operation of the induction motor is required to make the maximum power in a low voltage level. But the elements' temperature of the inverter increases due to high input current when it is in the ${\Delta}-connection$ operation. Therefore, the induction motor must be driven with the Y-connection. The lack of voltage needs to be with the field weakening control. This paper suggests the optimum field weakening control algorithm to drive the induction motor with maximum power in a limited thermal and DC voltage condition.

• International Journal of Internet, Broadcasting and Communication
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• v.10 no.1
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• pp.65-70
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• 2018

As technological development is progressing recently, various technologies are actively being studied in the course of the 4th industrial revolution. So, even in the educational field, virtual reality and augmented reality technology are used in educational environments, but specialized additional equipment is required and the price is very expensive. Also, since a plurality of equipment are required for a large number of people, it is urgent to study the technology that can be effectively applied to the industrial education field. So in this paper, we propose an industrial training system for HMD-AR, MPEG-DASH and SOAP based HTTP based Live Machinery Operation using Smartphone to solve the problems of existing system.

• Journal of the military operations research society of Korea
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• v.32 no.1
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• pp.36-50
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• 2006

It is required to transport a considerable amount of wartime strategic materials from US to Korea via airlift operation. This study attempts to formulate the wartime airlift operation model and evaluate the airlift capability of mobilized resources, including civil aircrafts. Although an airlift plan has been annually updated by the Korea Transportation Command, it is necessary to evaluate the feasibility through simulation due to uncertainties in the process of airlift operation. Uncertain parameters are as follows; the inter-arrival time of materials in the US airfields, loading and unloading times, the distribution of aircraft's initial location at the time of mobilization order. The simulation is executed under two scenarios and the results are analyzed through a sensitivity analysis. Simulation result shows that the irregularity of inter-arrival time and the number of mobilized civil aircrafts are the most critical factors in influencing airlift capability.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 2019.05a
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• pp.140-141
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• 2019

Busan Port is being operated inefficiently by a number of container terminal operators, which are dispersed in small groups. In particular, the small terminal at Busan Port is causing the dispersion of quantity, the increase of ITT cargo and the occurrence of a ship waiting at sea as the ship's Alliance became larger in 2016. As a result, studies such as integrated operations for the larger container terminals are being conducted. Therefore, in this study, we intend to set up a type of integrated operation for terminals at the new port of Busan and measure the practical effects through simulation to present an ideal direction for integrated operation.

• Journal of Korea Society of Digital Industry and Information Management
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• v.18 no.2
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• pp.17-26
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• 2022

In this paper, we propose a novel method of performing convolutional operations on a 2-D Processing Element(PE) array. The conventional method [1] of mapping the convolutional operation using the 2-D PE array lacks flexibility and provides low utilization of PEs. However, by mapping a convolutional operation from a 2-D PE array to a 1-D PE array, the proposed method can increase the number and utilization of active PEs. Consequently, the throughput of the proposed Deep Convolutional Neural Network(DCNN) accelerator can be increased significantly. Furthermore, the power consumption for the transmission of weights between PEs can be saved. Based on the simulation results, the performance of the proposed method provides approximately 4.55%, 13.7%, and 2.27% throughput gains for each of the convolutional layers of AlexNet, VGG16, and ResNet50 using the DCNN accelerator with a (weights size) x (output data size) 2-D PE array compared to the conventional method. Additionally the proposed method provides approximately 63.21%, 52.46%, and 39.23% power savings.

• Journal of the Korea Society of Computer and Information
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• v.22 no.2
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• pp.1-7
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• 2017

Recently, NAND flash memory, which is used as a storage medium, is replacing HDD (Hard Disk Drive) at a high speed due to various advantages such as fast access speed, low power, and easy portability. In order to apply NAND flash memory to a computer system, a Flash Translation Layer (FTL) is indispensably required. FTL provides a number of features such as address mapping, garbage collection, wear leveling, and hot data identification. In particular, hot data identification is an algorithm that identifies specific pages where data updates frequently occur. Hot data identification helps to improve overall performance by identifying and managing hot data separately. MHF (Multi hash framework) technique, known as hot data identification technique, records the number of write operations in memory. The recorded value is evaluated and judged as hot data. However, the method of counting the number of times in a write request is not enough to judge a page as a hot data page. In this paper, we propose hot data identification which considers not only the number of write requests but also the persistence of write requests.

• The Journal of Dong Guk Oriental Medicine
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• v.2 no.1
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• pp.155-166
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• 1993

Geukhachukeutang is used to cure blood stasis in Oriental Medicine. In order to investigate medical value on intravascula coagulation and contusion blood stasis, the effect of Platelet number, Fibrinogen quantity, Prothrombin time, FOP density, Paw edema increasing rate after prescribing Geukhachukeutang concentration liquid orally were observed. The obtained results are summerized as follows ; 1. Platelet number and Fibrinogen quantity are significantly increased, and Prothrombin time and FOP density are significantly decreased by Geukhachukeutang after inducing intravascula coagulation. 2. Platelet number and Fibrinogen quantity are not significantly increased, and Prothrombin time is not significantly decreased either, by Geukhachukeutang after inducing contusion blood stasis but Paw edema increasing rate is remarkablely decreased in three or four hours of the groups of prescribing. According to the above results, Geukhachukeutang will be used for contusion blood stasis and Intravascula coagulation effectively owing to being accepted as a favorable operation on Platelet number, Fibrinogen quantity, Prothrombin time, FDP density and Paw edema increasing rate.

• Journal of the Korea Institute of Military Science and Technology
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• v.14 no.5
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• pp.788-797
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• 2011

This paper analyzes the accuracy on the approach and landing of aircraft to an airport through comparison with airbase Precision Approach Radar and aircraft track data of DGPS equipped in aircraft. The proposed analysis result could be a basis for verifying the possibility that DGPS can be utilized in Airbase precision approach and landing. Position identification capability of widely used commercial DGPS is fairly accurate on latitude and longitude, while there is a slight error for being used in an airbase accurate approach and landing of Category I precision when it comes to altitude. Thus, we tested accuracy by analyzing actual flight track data of high performance aircraft to verify the accuracy of the airbase approach and landing using DGPS. Through the research, we developed instrumentation to compare PAR track data with DGPS track data, which can be used in reducing the number of PAR verification Flight utilizing it as a system measuring PAR accuracy at PAR installation phase.