• International Journal of Railway
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• v.1 no.3
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• pp.113-116
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• 2008

The long-tenn exposure of polymeric composite materials to extreme-use environments, such as pressure, temperature, moisture, and load cycles, results in changes in the original properties of the material. In this study, the effect of combined environmental factors such as ultraviolet ray, high temperature and high moisture on mechanical and thermal analysis properties of glass fabric and phenolic composites are evaluated through a 2.5 KW accelerated environmental aging tester. The environmental factors such as temperature, moisture and ultraviolet ray applied of specimens. A xenon-arc lamp is utilized for ultraviolet light and exposure time of up to 3000 hours are applied. Several types of specimens - tensile, bending, and shear specimens that are warp direction and fill direction are used to investigate the effects of environmental factors on mechanical properties of the composites. Mechanical degradations for tensile, bending and shear properties are evaluated through a Universal Testing Machine (UTM). Also, storage shear modulus, loss shear modulus and tan a are measured as a function of exposure time through a Dynamic Mechanical Analyzer (DMA). From the experimental results, changes in material properties of glass fabric and phenolic composites are shown to be slightly degraded due to combined environmental effects.

• Proceedings of the KSR Conference
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• 2002.10a
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• pp.484-489
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• 2002

Whenever the accidents occur in the railway areas, their prompt recovery is very important. The individual way has been used to resolve these accidents by direct visiting the site and reporting to others who cares for these cases. As a result, we are planning to operate the MTS (Moving picture Transmission System) for a timely information's transmission to the related peoples in the central control center by transforming the picture information on the accident-site to the digital information. The proposed system is not a transmission system using exclusive lines, but utilizing the existing railway computer network. We construct a network server device so that a dispatcher can easily connect with the server through the railway intranet. In some railway environments such as disturbed field situations and geographical condition(in tunnels and bridges, etc) building up the wired network is difficult. Solving this problem, we reviewed the wireless network. Finally we proposed the mixed wireless network that is able to cover the wired network. We then installed and tested the wired network and wireless network respectively in wayside of a railway field. Through the testing, we identified many detailed matters for some network construction approaches to the control room and many field device-connecting schemes. This research will contribute to minimize the number of staff dispatched to a disturbed field, decrease the accident recovery time and improve the quality of service to the passenger.

• Journal of Communications and Networks
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• v.6 no.1
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• pp.68-77
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• 2004

In the near future packet networks should support applications which can not predict their traffic requirements in advance, but still have tight quality of service requirements, e.g., guaranteed bandwidth, jitter, and packet loss. These dynamic characteristics mean that the sources can be made to modify their data transfer rates according to network conditions. Depending on the customer&; needs, network operator can differentiate incoming connections and handle those in the buffers and the interfaces in different ways. In this paper, dynamic QoS-aware scheduling algorithm is presented and investigated in the single node case. The purpose of the algorithm is in addition to fair resource sharing to different types of traffic classes with different priorities ?to maximize revenue of the service provider. It is derived from the linear type of revenue target function, and closed form globally optimal formula is presented. The method is computationally inexpensive, while still producing maximal revenue. Due to the simplicity of the algorithm, it can operate in the highly nonstationary environments. In addition, it is nonparametric and deterministic in the sense that it uses only the information about the number of users and their traffic classes, not about call density functions or duration distributions. Also, Call Admission Control (CAC) mechanism is used by hypothesis testing.

• Proceedings of the Korean Society of Broadcast Engineers Conference
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• 2015.07a
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• pp.527-530
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• 2015

2014 년 4 월 TTA 에서 개정된 "HTML5 기반 스마트 TV 플랫폼(TTAK.KO-07.0111/R1)" 표준의 멀티스크린 서비스는 UNnP, mDNS 등의 ZeroConf 네트워크 기술을 기반으로 스마트 TV 수신기가 스마트 폰이나 태블릿과 같은 다양한 컴패니언 디바이스를 발견하고 서로 연결하여 디바이스 간 연동 서비스를 구현할 수 있는 기술을 정의하고 있다. 또한, 이 멀티스크린 기술을 활용하여 개발된 서비스(앱)가 표준을 준수하는 다양한 수신기에서 동일한 사용자 경험(UX)으로 실행되기 위해서는 수신기가 멀티스크린 기술 요구 사항을 준수하여 구현되었는지를 검증하는 적합성 시험이 반드시 필요하다. 본 논문에서는 이러한 적합성 시험을 위한 시험 기준과 수행절차, 판정 기준 등을 정의하고 있는 " HTML5 기반 스마트 TV 플랫폼 수신기 적합성 시험(TTAK.KO-07.0119/R1)" 표준에 멀티스크린 시험을 위하여 추가된 시험 항목과 이를 실제로 실행하여 수신기를 검증하기 위하여 개발된 테스트케이스를 소개한다. 아울러, 컴패니언 디바이스에서 실행되면서 수신기의 테스트케이스와 연동하여 수신기 기능을 검증하는 데 활용하는 모바일 테스트 프레임워크와 이를 기반으로 하는 모바일 테스트케이스의 구현을 설명한다. 아울러, 본 논문에서는 TTA 에 구축된 멀티스크린 시험 환경에서 표준 기반 참조 수신기를 대상으로 멀티스크린 시험을 수행한 사례를 통해 시험환경의 유효성을 확인하고 향후 개선 방향을 제시한다.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.3 no.1
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• pp.63-68
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• 2002

In this paper harmonic diagnose tool is described for electric evaluate the power quality at industrial power systems is described both simulation and experimental testing during various operation conditions. PTW (Power Tools for Windows) and harmonic measuring instrument are organized around personal computer and/or instrumentation study environments interconnected via RS-232. Unknown zero sequence impedance data of cable is calculated by the modified T&D and BICC method. IEEE standard is also used to estimate the transformer input data. the proposed system provides a flexible and effective environment to diagnose the power quality at industrial distribution systems by utilizing simulations and actual field data.

• KIPS Transactions on Computer and Communication Systems
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• v.3 no.10
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• pp.365-370
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• 2014

Although Internet of Things already became a new paradigm on service on network, we should pay more effort for studying about its testing method, since humans, things and environments in IoT are connected to each other without any restrictions. Earlier researches based on emulators showed that such virtual devices on emulators had unavoidable gap between them and real things. Furthermore, growth of connection complexity between the devices and loosing of restrictions make the gap wider. Accordingly, in this paper, we suppose a method of test coverage measurement based on BitTorrent for IoT environment. It has cooperation features among homogeneous devices with avoiding the overlapping on each part of whole test process.

• The Journal of Asian Finance, Economics and Business
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• v.8 no.10
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• pp.65-76
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• 2021

This study aims at investigating the effect of product innovation accounting on the market success of instant food and convenience food businesses in Thailand with customer response capability as the mediator. In addition, it examines the effects of management accounting systems, marketing intelligence, and technology orientation on product innovation accounting. The sample for this study is 258 instant food and convenience food businesses in Thailand. To test the research relationships, a structural equation model is used. The results of this study show that product innovation accounting has a significant effect on both customer response capability and market success. Similarly, customer response capability significantly leads to market success while it mediates the product innovation accounting-market success relationship. Testing the antecedents of the research relationships, management accounting system, marketing intelligence, and technology orientation potentially affect product innovation accounting. Accordingly, product innovation accounting is a key source of competitive advantage. Product innovation accounting must be recognized by company management as a strategic tool for competing in markets and environments. They must invest their resources and capabilities to create and develop product innovation accounting principles, as well as encouraging their staff to implement and use these principles in the workplace.

• Journal of the Korea Society of Computer and Information
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• v.24 no.3
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• pp.77-86
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• 2019

The advent of Internet of Things (IoT) makes common nowadays computing environments involving programming not a single computer but several heterogeneous distributed computers together. Developing programs separately, one for each computer, increases programmer burden and testing all the programs become more complex. To address the challenge, this paper proposes an RPC-based unified programming language, UniPy, for development of MGC (eMbedded, Gateway, and Cloud) applications in IoT systems configured with popular computers such as Arduino, Raspberry Pi, and Web-based DB server. UniPy offers programmers a view of classes as locations and a very simple form of remote procedure call mechanism. Our UniPy compiler automatically splits a UniPy program into small pieces of the program at different locations supporting the necessary RPC mechanism. An advantage of UniPy programs is to permit programmers to write local codes the same as for a single computer requiring no extra knowledge due to having unified programming models, which is very different from the existing research works such as Fabryq and Ravel. Also, the structure of UniPy programs allows programmers to test them by directly executing them before splitting, which is a feature that has never been emphasized yet.

• Geomechanics and Engineering
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• v.17 no.5
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• pp.475-483
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• 2019

Vegetation cover plays a vital role in stabilizing the soil structure, thereby contributing to surface erosion control. Surface vegetation acts as a shelterbelt that controls the flow velocity and reduces the kinetic energy of the water near the soil surface, whereas vegetation roots reinforce the soil via the formation of root-particle interactions that reduce particle detachment. In this study, two vegetation-testing trials were conducted. The first trial was held on cool-season turfgrasses seeded in a biopolymer-treated site soil in an open greenhouse. At the end of the test, the most suitable grass type was suggested for the second vegetation test, which was conducted in an environmental control chamber. In the second test, biopolymers, namely, starch and xanthan gum hydrogels (pure starch, pure xanthan gum, and xanthan gum-starch mixtures), were tested as soil conditioners for improving the water-holding capacity and vegetation growth in sandy soils. The results support the possibility that biopolymer treatments may enhance the survival rate of vegetation under severe drought environments, which could be applicable for soil stabilization in arid and semiarid regions.

• Journal of Aerospace System Engineering
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• v.13 no.3
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• pp.40-47
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• 2019

This paper proposes the environment construction and test method of system integration laboratory (SIL) and system integration test (SIT) for verification of interface between onboard equipment and ground control equipment of unmanned aerial systems (UAS). This research also describes the interface environment between subsystems built in SIL and verification methods for the systems' operation logic through simulated flights. Similarly, the paper handles the ground integration test process of UAS in the real testing environments.