• Journal of the Korea Academia-Industrial cooperation Society
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• v.15 no.10
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• pp.5899-5905
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• 2014

Faults in electric power system can be a critical problem for vehicles. The system durability is determined mainly by the durability of their components and operating conditions. Monitoring the conditions of the electric power system may be necessary because it is very difficult to predict precisely when it will fail. Therefore, the aim of this study was to develop a diagnosis system for an electric power system of a vehicle. The alternator voltage, excitation voltage, lamp voltage, battery voltage, and engine rpm from a crank angle sensor are monitored continuously and the system fault can be then detected in real time. NI USB- 9201 DAQ and LabVIEW SW have been used to measure the voltages and analyze the data. Compared to conventional measurements for only each component, an integrated and portable measurement method was developed. In addition to the monitoring the electric power system in real time, the saved data from the measurement also provides valuable information to improve the durability of the components.

• 제어로봇시스템학회:학술대회논문집
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• 1991.10b
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• pp.1705-1711
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• 1991

On-line fault detection and diagnosis has an increasing interest in a chemical process industry, especially for a process control and automation. The chemical process needs an intelligent operation-aided workstation which can do such tasks as process monitoring, fault detection, fault diagnosis and action guidance in semiautomatic mode. These tasks can increase the performance of a process operation and give merits in economics, safety and reliability. Aiming these tasks, series of researches have been done in our lab. Main results from these researches are building appropriate knowledge representation models and a diagnosis mechanism for fault detection and diagnosis in a chemical process. The knowledge representation schemes developed in our previous research, the symptom tree model and the fault-consequence digraph, showed the effectiveness and the usefulness in a real-time application, of the process diagnosis, especially in large and complex plants. However in our previous approach, the diagnosis speed is its demerit in spite of its merits of high resolution, mainly due to using two knowledge models complementarily. In our current study, new knowledge representation scheme is developed which integrates the previous two knowledge models, the symptom tree and the fault-consequence digraph, into one. This new model is constructed using a material balance, energy balance, momentum balance and equipment constraints. Controller related constraints are included in this new model, which possesses merits of the two previous models. This new integrated model will be tested and verified by the real-time application in a BTX process or a crude unit process. The reliability and flexibility will be greatly enhanced compared to the previous model in spite of the low diagnosis speed. Nexpert Object for the expert system shell and SUN4 workstation for the hardware platform are used. TCP/IP for a communication protocol and interfacing to a dynamic simulator, SPEEDUP, for a dynamic data generation are being studied.

• Journal of Korean Society of Disaster and Security
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• v.9 no.1
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• pp.33-38
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• 2016

Real time location system was development for safety management at road and bridge maintenance field. The system can check the real-time location detection, movement history, behavior of a number of laborers. The system consisted of a Bluetooth and ZigBee that uses low-power. It had a very large error that the previous method for the position recognition by triangulation using the RSSI. Because This study proposed a new distance measurement and correction scheme using RSSI and accelerometer. It was evaluated in the maintenance field. A development system were evaluated in the field, the results are shown an error between 0.2 m and 0.4 m. And through the acceleration of history it was confirmed by determining possible to determine the safety situation of the laborers.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.35 no.7
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• pp.701-707
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• 2011

The aim of this paper is to develop a collaborative design system that can facilitate remote modification and control of a 3D solid model through the Internet. It enables the users to resolve conflicting viewpoints about an issue and collaborate to design a tangible object within a given set of constraints. In order to optimize the collaborative design system, we focus on the results obtained by using the collaborative design method for the real-time modification of a 3D solid model in a distributed environment. It also provides the method of managing the consistency between design entities. The efficiency of the system is verified by implementing it in a distributed environment.

• Journal of Korean Tunnelling and Underground Space Association
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• v.18 no.3
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• pp.331-339
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• 2016

Real time location (RTL) system which can control the safety of laborers in the underground space is developed in this study. This innovative system can monitor the location and history of movement of multiple laborers in real time. To accommodate constrains of the underground space, the system is portable and composed with low-battery mode. Since conventional method to detect the location of laborer with radio signal strength indicator (RSSI) contains high errors, new measurement system using accelerometers and correction method are suggested in this study. Field test is performed to validate the developed system. The error for moving laborer was 0.4 m and for non-moving laborers was 0.2 m. Thus, it is found that the new RTL system can be used to monitor the location of laborers in the underground construction space.

• Journal of the Optical Society of Korea
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• v.16 no.2
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• pp.121-126
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• 2012

We propose a novel technique that records the horizontal-parallax-only (HPO) hologram of a real object using optical scanning holography (OSH). The proposing HPO-OSH is composed of a conventional OSH and an electronics low pass filter. When we scan an object along vertical direction before horizontal direction, the electronic low pass filter filters the vertical fringes with preserving horizontal fringes and gives an HPO hologram. To the best of our knowledge, this is the first time to record the HPO hologram using OSH without either truncation of the scanning beam or digital post processing.

• Proceedings of the KSME Conference
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• 2003.04a
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• pp.2005-2011
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• 2003

Introducing the interfacial pressure jump terms based on the surface tension into the momentum equations of two-phase two-fluid model, the system of governing equations is turned mathematically into the hyperbolic system. The eigenvalues of the equation system become always real representing the void wave and the pressure wave propagation speeds as shown in the previous manuscript. To solve the interfacial pressure jump terms with void fraction gradients implicitly, the conventional semi-implicit method should be modified as an intermediate iteration method for void fraction at fractional time step. This advanced semi-implicit method (ASIM) then becomes stable without conventional additive terms. As a consequence, including the interfacial pressure jump terms with the advanced semi-implicit method, the numerical solutions of typical two-phase problems can be more stable and sound than those calculated exclusively by using any other terms like virtual mass, or artificial viscosity.

• Proceedings of the Korean Society of Agricultural Engineers Conference
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• 2002.10a
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• pp.245-248
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• 2002

The Soil Conservation Service (SCS) developed a unique procedure for estimating direct runoff from storm rainfall. But, It is very difficult to estimate accurately flood hydrograph by SCS method, because the initial ion of Ia(0.2Sa) itself has lots of systematic errors and there is no investigation on Ia in the Korean watershed. The maximum storage capacity of Umax is calibrated in the DAWAST model and is related to the present ability of rainfall to be infiltrated into the unsaturated soil. Effective rainfall for design and real-time flood hydrograph can be estimate more reasonably by introducing new Ia relationship made from the rainfall-runoff data observed in the Korean watersheds.

• Journal of Korea Game Society
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• v.7 no.2
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• pp.101-112
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• 2007

Along with the development of mobile technology, mobile game has undergone a change from downloadable game to network game, where a large number of users connect to server and play real-time game with a mobile phone. In order to develop these mobile network games economically, a proper, suitable game engine is needed. This study proposes the result of design and implementation of RWMMO-GE(Realtime Wireless Massively Multiplayer Online RPG Game Engine) that is used to develop a mobile network game. The structure of RWMMO-GE, which is the research result of this study, consists of major components such as Network/Client Module, Object Module, Map Tool, Script Editor, and Character Editor. The characteristics of the multiplayer mobile game developed by this engine is that a large number of players can play real-time game in a single map, which implies a possibility of a new business model in this area. This research is a result of the RWMMO-GE supported by 2006 IT Excellent Technology Support Project(No:A1300-0601-0125) of IITA(Institute Information Technology Advancement).

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.22 no.3
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• pp.264-274
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• 2012

Evaluation on the environmental noise is carried out by surveying subjective response of residents with physical measurement of noise during long period in field. Particularly field survey is used to make regulations from the analysis on how many people are annoyed for specific noise level, and laboratory test used to analyze the relationship between physical parameters of noise and subjective responses. In the laboratory controlling the variables is easy but the results could be biased because the condition in room would be different with field. Most of all noise exposure time is considered to be different with real situation, and this study aimed to evaluate the subjective response by exposure time of transportation noise, by applying three kinds of variable how much they give effects on the annoyance as the exposure time is operating condition, windows type and sound level. As a result there was somewhat difference between operating type and annoyance, which is caused by the sound characteristics operated in different condition. However the window type didn't give much effect to the annoyance as much as sound type. This means that the subjective response could give similar result by exposure time even for different window types. Most of all, the main factor affecting subjective response is considered to be the sound level and the exposure time.