• Journal of the Korea Institute of Information and Communication Engineering
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• v.10 no.8
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• pp.1443-1448
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• 2006

As computers and networks become popular, distributing information on the Internet is common in our daily life. In the past, e-mail has been the primary choice of exchanging information but messengers are gaining popularity abroad and domestically because of their nature of getting immediate responses. Information leakage by invasion that is enemy of evil in communication of communications division Server and Agent between each agents that become burden of communication for effective administration of data for most of existing messenger is becoming an issue. In this paper, we design a secure messenger system that could be obtained maximum security. It use ECC based on ElGamal methodology using PKI for secure communication. For the message encryption and decryption between the same group non, each group is kept distinct by drawing an elliptic curve and an arbitrary point is chosen on the curve.

• Journal of Navigation and Port Research
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• v.28 no.6
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• pp.557-564
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• 2004

The WAM wave model has been widely used for wave hindcasting in the ocean by many domestic and foreign researchers due to its relative simplicity and high accuracy. As this model was originally developed for the condition of deepwater and comparatively coarse grid size covering wide area, it might produce in a fault result caused by the improper distribution of directional spreading. We extensively investigated involved problems based on WAM Cycle 4 model and suggested the improved WAM model so that it is applicable to both shallow water sea and fine mesh wave simulation The modified W AM model is verified here by comparing the computed result with and the observed data at Ieodo Ocean Research Station for September of 2003.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.38 no.3
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• pp.337-344
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• 2014

An optimal shape design algorithm is suggested to systematically design a traditional Korean musical instrument, the Pyeongyeong. The Pyeongyeong consists of 16 different chime stones called Gyeongpyeons. The first natural vibration frequency of each Gyeongpyeon must be adjusted to its target frequency, which is determined by the traditional sound tuning method. The second and third natural frequencies must be proportional to the first natural frequency with a specific ratio (1:1.498:2.378). The key idea in our suggested design algorithm is to use the sensitivity of natural frequencies to the variation in the length of each side of a Gyeongpyeon. The dimensions of five different Gyeongpyeons are determined by following the suggested algorithm. Changes in natural frequencies with respect to local thickness variation are closely investigated to compensate for errors that may occur during manufacturing.

• The Journal of Engineering Geology
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• v.17 no.1 s.50
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• pp.41-47
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• 2007

Geotechnical Phenomena such as landslide, groundwater recharge and groundwater fluctuation due to rainfall can be explain to use a dielectric response and infiltration variation by the movement of a wetting front in the subsurface. The infiltration of a wetting front is infiltrating to the connected pores which are distributed in unsaturated soil. In this study we carried out to laboratory experiment of a vertical infiltration column test using ethanol mix-ing tracer which has same the specific gravity of water. All physical values are detected to use a variation of dielectric constant and calculated to use a dielectric mixing model and tracer test model. This dielectric method measured by each dielectric constant of geological soil porous materials should be of for the geotechnical information and useful a field monitoring technique for detecting the variations of the volumetric water content and the wetting front, which are insignificant the key parameter to understanding the landslide by rainfall.

• Journal of Korea Game Society
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• v.17 no.1
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• pp.7-16
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• 2017

The 3D game graphic technology has become an important factor in the contents field with the game contents development. In particular, game character technology provides a realistic technique and visual pleasure, as well as an intermediate step in the immersion of the game in which the game might create an optical illusion that enables the player to enjoy heroic adventure in the game. The high expression level of characters in 3D games is a key factor in the development process, with details and carefulness of the character setting work [3]. In this paper, we propose a character representative technique applied to mobile games using mathematical model of radiosity energy, spectral radiance model, and ray tracing model method using 3D unity game engine with sensible AI algorithm for game implementation. As a practical application to the game contents, it was found that the projection of the surface in the rendering process and the game simulation might change according to the lighting condition of the game content environment, so that the high quality of game characters was simulated.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.16 no.3
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• pp.203-211
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• 2016

The genetic code is a key to bio-informatics and to a science of biological self-organizing on the whole. Modern science faces the necessity of understanding and systematically explaining mysterious features of ensembles of molecular structures of the genetic code. This paper is devoted to symmetrical analysis for genetic systems. Mathematical theories of noise-immunity coding and discrete signal processing are based on Jacket matrix methods of representation and analysis of information. Both of the RNA and Jacket Matrix property also have the Element(Block) - wise Inverse Matrices. These matrix methods, which are connected closely with relations of symmetry, are borrowed for a matrix analysis of ensembles of molecular elements of the genetic code. This method is presented for its simplicity and the clarity with which it decomposes a Jacket Matrix in terms of the genetic RNA Codon.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.56 no.2
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• pp.155-162
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• 2020

The adjudication of Korean Maritime Safety Tribunal (KMST) was analyzed to collect basic data to identify the cause of the risk that did not appear in the current data provided by the fishermen's occupational accidents of the National Federation of Fisheries Cooperative (NFFC) in stow net fishing vessel from 2015 to 2019. The personnel's carelessness was the most common in 29 out of 33 accidents (87.9%), followed by 25 cases (75.8%) of inadequacy of instructions, 24 cases (72.7%) of inadequacy of education on hazard factor, 20 cases (60.6%) of no personal protection equipment, 18 cases (54.5%) of poor guard, 17 cases (51.5%) of inadequacy of work method, 16 cases (48.5%) of absence of emergency stop button, 14 cases (42.4%) of work practice of poor safety precautions that affected more than 40% of all accidents as accident causes. These causes had a strong influence on each other, and the ratio of accident causes is high. With this relationship, accidents can be prevented or the severity of human injury can be reduced if types of accident process can be estimated with a scenario, and the key points before the accident in the scenario are switched to safe points.

• Journal of Convergence for Information Technology
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• v.10 no.11
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• pp.16-22
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• 2020

Since it is difficult for individual power producers and non-professionals who lack basic knowledge to control, manage, and operate facilities through EMS (Energy Management System), augmented reality and virtual reality monitoring systems are applied. However, in the existing systems, data access efficiency is inferior due to the process of analyzing column values for analog signal values collected from sensors and converting data after combining the columns. In addition, high-speed operation processing is difficult due to a large number of indexes for accommodating access patterns for various analog signal waveforms. Therefore, in this paper, a bitmap generator is inserted into a non-tree structure to convert the data collected from power facilities into physical property information, and the converted information is encrypted with a common key, so that the resources for the resources shared between each device are We propose a method of exchanging data for an augmented reality-based power system that is controlled by measurement.

• Transactions of the Korean hydrogen and new energy society
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• v.23 no.4
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• pp.300-309
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• 2012

Long endurance is a key issue in the application of unmanned aerial vehicles. This study presents feasibility test results when fuel cell system as an alternative to the conventional engine is applied for the power of the UAV after the 150W fuel cell system is developed and packaged to the 1/4 scale super cub airplane. Fuel cell system is operated by dead-end method in the anode part and periodically purged to remove the water droplet in flow field during the operation. Oxygen in the air is supplied to the stack by the two air blowers. And fuel cell stack is water cooled by cooling circuit to dissipate the heat generated during the fuel cell operation. Weight balance is considered to integrate the stack and balance of plant (BOP) in package layout. In flight performance test, we demonstrated 4 times standalone take-off and landing. In the laboratory test simulating the flight condition to quantify the energy flow, the system is analyzed in detail. Sankey diagram shows that electric efficiency of the fuel cell system is 39.2%, heat loss 50.1%, parasitic loss 8.96%, and unreacted purged gas 1.67%, respectively compared to the total hydrogen input energy. Feasibility test results show that fuel cell system is high efficient and appropriate for the power of UAV.

• Journal of Navigation and Port Research
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• v.34 no.3
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• pp.243-249
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• 2010

The competition between ship management companies is fierce as a result of global trend towards increased specialization. In order for ship management companies to remain competitive, it is necessary to understand the local and global factors and the changing circumstances that impact shipping markets and trade patterns. To better understand these factors, a study and analysis of drawing priority of the competitiveness-evaluation factors of ship management companies was conducted using Analytical Hierarchy Process(AHP) as a method dealing with dicision-making problem. As a consequence of this analysis, it was determined that human resources, both shipboard and land management, were a primary factor in ship management company's competitiveness. Thus, the acquisition and retention of capable staff was a key aspect of assuring a ship management company's competitiveness.