• Journal of the Korea Academia-Industrial cooperation Society
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• v.21 no.9
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• pp.380-386
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• 2020

The ESS load test device (ELTD) can store and exchange electrical energy during the load test of an emergency generator. On the other hand, it is difficult to commercialize ELTDs based on Li-ion batteries because of the high initial cost, which is higher than a load bank test. If the trade of electrical energy stored in ELTD during the test of an emergency generator is considered, it may be possible to commercialize the ELTD. Therefore, this paper proposes an economic model of ELTD composed of the costs and benefits by considering electrical energy trade to perform accurately economic evaluations of an ELTD. From the simulation results of the economic evaluations of an ELTD and the load bank method, it was found that the commercialization of ELTD is possible when the trade in electrical energy in ELTDs is considered.

• Proceedings of the Korea Contents Association Conference
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• 2011.05a
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• pp.351-352
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• 2011

운전면허 시험이 존재하는 동안 운전면허 학과시험은 필수적인 시험제도로 존재 할 것이며 향후 상당기간동안 지속적으로 산업화가 될 것으로 전망 된다. 그러나 기존의 서적을 통한 학습은 이미 출제 되었던 문제로 지정된 상황에 대한 대처 방법을 평가하는 것에 지나지 않는다. 또한 운전면허 학원에서 학과시험을 취득 할 경우 과도한 시간과 경비가 소요할 뿐만 아니라 학습효과 면에서도 비효율적인 것으로 평가되고 있다. 때문에 학습자의 능력, 연령 등을 고려한 맞춤형 운전면허 학과시험 시스템의 시급의 도입이 시급하며 이를 편리하게 학습 할 수 있는 E-Learning 멀티미디어 콘텐츠 개발이 필요하다. 이에 본 연구는 이러한 필요성에 따라 학습자의 상황에 맞는 맞춤형 교육이 이루어 질 수 있는 맞춤형 운전면허 학과시험 학습 시스템을 제안하고자 한다. 이를 통해 학습자의 문항반응의 오답분석을 통하여 최적의 평가문제와 학습콘텐츠를 선택하여 학습자에게 제공하는 과정을 반복함으로써 동적 맞춤형 E-Learning 학습방식을 제공하고, 난해한 교통 법규를 쉽고 재미있게 학습할 수 있을 것으로 기대해 본다.

• Journal of the Institute of Electronics Engineers of Korea TE
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• v.37 no.1
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• pp.58-62
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• 2000

We Propose modulation scheme using I-Q modulation for transmitting different information simultaneously. For transmitting 1bit of each information, we apply QPSK scheme, for more bits, MAPSK. At the second modulation stage, We mix PN wavefoms with APSK waveforms for spreading bandwith. BER(Bit Error Rate) of each Information of the proposed scheme is analyzed on computer simulation. Finally we show power spectrum before and after spreading bandwidth.

• Journal of the Korean Association of Geographic Information Studies
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• v.14 no.4
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• pp.161-171
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• 2011

Most public organizations which charge for measuring or collecting environmental information provide web-based information services. In the case of Seoul, it is provided smart phone app for information services on region or district unit. However, there is no smart phone application for environment information services considering location-based services with the concept of personalization. The purpose of this study is to deign and implement a smart phone app for air environment and radioactive information services with these features. Hybrid type is adopted, so that several things are possible: access to a variety of devices by web languages, and N-Screen support is available. According as social needs with respect to more environmental information and their contents are increasing, this approach will be useful.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.38 no.6
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• pp.620-628
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• 2010

Small satellites can be used for various space research and scientific or educational purposes due to advantages in small size, low-cost, and rapid development. Small Satellites have many advantages of application to Responsive Space. Compared to traditional larger satellites, however, Small satellites have many constraints due to limitations in size. Therefore, it is difficult to expect high performance. To approach maximum capability with minimal size, weight, and cost, standard modular platform of Small satellites is necessary. Modularity supports plug-and-play architecture. The result is Small satellites that can be combined quickly and reliably using plug-and-play mechanisms. For communication between modules, standard bus interface is needed. Controller Area Network(CAN) protocol is considered optimum data bus for modular Small satellite. CAN can be applied to data communication with high reliability. Hence, design optimization and simplification can also be expected. For ease of assembly and integration, modular design can be considered. This paper proposes development method for standardized modular Small satellites, and describes design of data interface based on CAN and a method of testing for modularity.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.46 no.1
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• pp.52-58
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• 2018

A Study on the dynamic characteristics of a rotor driven by a tipjet system in hovering condition was carried out. The sectional modeling was performed for the tipjet blade in which the flow path was inserted, and the dynamic characteristics analysis was conducted by modeling the components of the proposed rotor system. The analysis was conducted with respect to the rotational speed and the collective pitch. As a result of the analysis, it was checked that the proposed tipjet rotor did not have aeroelastic instability within the designed operating range. The tipjet test equipment was constructed in order to verify the analysis approach. It was confirmed that the proposed rotor was driven normally by tipjet. The non-rotating eigenmode measurement test and the rotation test were performed, and the validity was proved by comparing the test results and the analysis results.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.41 no.10
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• pp.827-832
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• 2013

Heating wire cutting type separation mechanism has been widely used for cube satellite applications due to its design constraints such as small size of $10cm{\times}10cm{\times}10cm$ and light weight of less than 1kg. In addition, usage of pyro technic device is not allowed for cube satellite application. The conventional methods have some disadvantages of relatively small mechanical constraint force and the system complexity for the multi-deployable systems. In this paper, a separation nut type non-explosive separation mechanism has been proposed and investigated. The effectiveness of the design has been verified through the qualification tests of the mechanism.

• Journal of the Korea Institute of Building Construction
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• v.18 no.5
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• pp.463-469
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• 2018

A currently used roof green system with multi layers has a low constructability. Therefore a new integrated waterproof & root barrier sheet and roof green box unit system was developed using steel plate fixture and cone type fixture by electromagnetic induction heating method. This study was proceeded to evaluate adhesion performance of two types of fixtures on Engineering PE, TPO, PVC sheet in a normal condition, repeated heating and cooling condition. As a result, adhesion load on Engineering PE sheet showed the highest value. The adhesion loads of steel plate fixture showed higher value as heating temperature was getting higher. However adhesion loads of cone type fixture showed opposite tendency. Regarding to the test conditions, test results of normal condition, repeated heating and cooling condition showed same value. The cone type fixture using butyl tape showed 7 times lower adhesion load than that of cone type fixture using electromagnetic heating and 28% lower adhesion load in a repeated heating and cooling condition than a usual condition.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.30 no.7
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• pp.144-149
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• 2002

This paper presents a technique for real time multiprocessor parallel processing to develop an avionic system computer(ASC) which integrates the avionics control, navigation and fire control, cursive and raster graphic symbol generation into one line replaceable unit. The proposed method has optimal performance by adopting a logically asymmetric structure between four 32bit RISC processors based on the master-slave multiprocessing, a tightly coupled interaction level with the time shared common bus and global memory, and an efficient bus arbitration algorithm. The ASC has been verified through a series of flight tests. The relevant tests also have been rigorously conducted on the prototype ASC such as electrical test, environmental test, and electromagnetic interference test.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.44 no.3
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• pp.274-280
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• 2016

Hinge driving type holding and release mechanism based on the burn wire release for application of cubesat is main payload of STEP Cube Lab. (Cube Laboratory for Space Technology Experimental Project) to be launched at 2015. It has high constraint force, low shock level as well as surmounting drawbacks of conventional nichrome burn wire release method that has relatively low constraint force and system complexity for application of multi-deployable systems. In this paper, we have proposed a flight model of holding and release mechanism for the verification of the constraint force and deployment status signal acquisition. To validate the effectiveness of the flight model, launch and on-orbit environment verification test have been performed.