• Journal of Satellite, Information and Communications
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• v.7 no.2
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• pp.104-109
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• 2012

Currently, GPS(Global Positioning System) is used to find user location information. However, in some cases, especially in urban environments, we receive unreliable location information deu to multipath fading. In order to resolve this problem, we propose a closely coupled positioning technique where GPS signal is combined with QZSS signal. Also we proposed and analyze a combining algorithm of GNSS and Wi-Fi signals to get closely coupled location information by referring AP information. Finally, this paper proposes a combined GPS/QZSS/Wi-Fi navigation algorithm to improve navigation performance, and it is verified by testing of car deriving according to availability and accuracy standard.

• Journal of KIISE:Computing Practices and Letters
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• v.6 no.1
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• pp.93-102
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• 2000

Processors for a base station controller such as call control processor have to serve usersdemand. Some of processors have been still used for the processing of call and 0&M (operation and maintenance) management by adopting embedded board type. This type can not provide users with a wide variety of environments for testing and debugging. User environments are regarded as a primary system factor in most systems and this is particularly so in designing and implementing the processor for base station controller in mobile communication systems. We describe the design and implementation of new user environment tool named QUEST for the next generation mobile communication system, IMT-2000. The simulation results of performance evaluations demonstrate that our system performs well for a base station controller without performance degradation.

• Journal of the Korea Institute of Military Science and Technology
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• v.25 no.5
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• pp.443-461
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• 2022

Target Detection in synthetic aperture radar(SAR) image is critical for military and national defense. In this paper, we propose YOLOv4-Attention architecture which adds attention modules to YOLOv4 backbone architecture to complement the feature extraction ability for SAR target detection with high accuracy. For training and testing our framework, we present new SAR embedding datasets based on MSTAR SAR public datasets which are about poor environments for target detection such as various clutter, crowded objects, various object size, close to buildings, and weakness of signal-to-clutter ratio. Experiments show that our Attention YOLOv4 architecture outperforms original YOLOv4 architecture in SAR image target detection tasks in poor environments for target detection.

• Journal of the Korean Society for Nondestructive Testing
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• v.32 no.6
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• pp.637-647
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• 2012

Bridges are ones of fundamental facilities for roads which become social overhead capital facilities and they are designed to get safety in their life cycles. However as time passes, bridge can be damaged by changes of external force and traffic environments. Therefore, a bridge should be repaired and maintained for extending its life cycle. The working load on a bridge is one of the most important factors for safety, it should be calculated accurately. The most important load among working loads is live load by a vehicle. Thus, the travel characteristics and weight of vehicle can be useful for bridge maintenance if they were estimated with high reliability. In this study, a B-WIM system in which the bridge is used for a scale have been developed for measuring the vehicle loads without the vehicle stop. The vehicle loads can be estimated by the developed B-WIM system with the reaction responses from the supporting points. The algorithm of developed B-WIM system have been verified by numerical analysis.

• Journal of Electrical Engineering and Technology
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• v.9 no.6
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• pp.1851-1863
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• 2014

Many countries are increasing their investments in smart grid technology to enhance energy efficiency, address climate change, and trigger a green energy revolution. In addition to these goals, Korea also seeks to promote national competitiveness, prepare for the growth of the renewable energy industry, and export industrialization through its strategic promotion of the smart grid. Given its inherent representativeness for Korean implementation of the smart grid and its growth potential, Jeju Island was selected by the Korean government as the site for smart grid testing in June 2009. This paper presents a new design for the electricity market and an operational scheme for testing Smart Electricity Services in the Jeju smart grid demonstration project. The Jeju smart grid test-bed electricity market is constructed on the basis of day-ahead and real-time markets to provide two-way electricity transaction environments. The experience of the test-bed market operation shows that the competitive electricity market can facilitate the smart grid deployment in Korea by allowing various demand side resources to be active market players.

• ETRI Journal
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• v.18 no.4
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• pp.265-286
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• 1997

This paper presents a new software development environment that supports an integrated methodology for covering all phases of software development and gives integrated methods with tools for ITUT (Telecommunication Standardization Section of the International Telecommunication Union) languages. The design of the environment to improve software productivity and quality is based on five main concepts: 1) formal specifications based on SDL (Specification and Description Language) and MSC (Message Sequence Charts) in the design phase, 2) verification and validation of those designs by tools, 3) automatic code generation and a safe separate compilation scheme based on CHILL (CCITT High-Level Language) to facilitate programming-in-the-many and programming-in-the-large. 4) debugging of distributed real-time concurrent CHILL programs, and 5) simulation of application software for integrated testing on the host machine based on CHILL. The application results of the environment compared with other approaches show that the productivity is increased by 19 % because of decreasing implementation and testing cost, and the quality is increased by 83 % because of the formal specifications with its static and dynamic checking facilities.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.31 no.5B
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• pp.405-412
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• 2006

In this paper, we present an efficient method for simulating massively virtual clients in an online game environment. Massively multi-player online games and other multi-user based networked applications are becoming more attractive to the gamer players. Such kind of technology has long been researched in the area called Networked Virtual Environments. In the game development process, a set of beta tests is used to ensure the stability of online game servers. A set of testing processes consumesa lot of development resources such as cost, time, and etc. The purpose of VENUS system is to provide an automated beta test environment to the game developers to efficiently test the online games to reduce development resources.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.30 no.11A
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• pp.987-994
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• 2005

Most of the proposed SRGMs are required to perfect debugging based on removal of defect as soon as the detection of defects in system tests. But the detected defects are corrected after few days as a fixed time or induced new fault in software under the imperfect debugging environments. Solving these problems, we discussed that the formal software reliability model considered testing-effort for the fault detection and correction of software defects, and then using this model we have estimated of the software reliability closed to practical conditions.

• International Journal of Oral Biology
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• v.35 no.4
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• pp.185-190
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• 2010

Methicillin-resistant Staphylococcus aureus (MRSA) is one of the most prevalent pathogens in hospitals. To investigate cross contamination by this bacterium in both dental and medical settings, the pathogens that cause acute pyogenic infection and one of the major microbes responsible for nosocomial infection were isolated from health care providers, nurses and patients. We used VITEK II to measure drug sensitivity, and we further performed biochemical testing, coagulase serotype testing and pulse-field gel electrophoresis (PFGE) for isolated MRSA colonies. The isolation rate of Staphylococcus aureus from nasal swabs was 75.0% from dental health care providers and 18.8% from the medical health care providers. A total of 10 MRSA strains were isolated from 40 health care providers and 2 patients and the prevalent coagulase serotype from patients and health care providers was VII. The antimicrobial drug resistance and partial PFGE types of the isolated MRSA strains showed a similar pattern. These results suggest that MRSA may be one of the principal causes of nosocomial infection in dental and medical hospitals.

• Journal of Korean Institute of Industrial Engineers
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• v.28 no.4
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• pp.407-414
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• 2002

The inherent reliability of a product is primarily determined in the design stage, and therefore, design engineers should be able to design reliability into the product in an efficient manner. Especially, the product should be designed such that its reliability is robust to various noise factors encountered in production and field environments. The Taguchi method can be effectively used for this purpose. However, there exist only a few attempts to integrate the Taguchi method with reliability design, and in addition, the existing works do not sufficiently consider the robustness and/or the distinction between noise and acceleration factors. This paper develops a unified approach to robust reliability design assuming that accelerated life tests are conducted at each combination of design and noise conditions. First, an experimental structure for assigning not only acceleration but also noise factors is presented. Second, the reliability at the use condition is estimated using the assumed accelerated life test model. Third, reliabilities are transformed into 'efforts' using an effort function which reflects the degree of difficulty involved in improving the reliability. Finally, an optimal setting of design parameters is determined based on the mean and standard deviation of the effort values. The above approach is illustrated with an example of a paper feeder design.