• Proceedings of the Korean Society of Broadcast Engineers Conference
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• 2003.11a
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• pp.75-78
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• 2003

MPEG-4 표준은 저작자가 정지영상, 텍스트, 2D/3D 그래픽스, 오디오, 심지어 임의형의 비디오 등과 같이 다양한 형태의 객체들을 개별적으로 구성하고 이들을 시/공간자적으로 다루기 용이하게 해 준다. 이와 같은 객체 기반 코딩 특성에 의해서 대화형 방송 콘텐츠를 제작하는데 가장 유용한 방식으로 고려할 수 있다. 피러나, 콘텐츠의 제작, 전송, 소비 관전에서 고려해 달 때, 콘텐츠 제작자 또는 저작권자의 보호 및 관리가 필요하게 되었다. 이에 따라 최근에는 OPIMA (Open Platform Initiative for Multimedia Access), SDMI (Secure Digital Music Initiative) and MPEG(Moving Picture Expert Group) OPIMATfMr(Intellectual Property Management & Protection)와 같은 국제 표준 단체들이 콘텐츠 보호 및 관리에 대한 관심을 가지게 되었다. 특히, MPEG의 경우에 MPEG-4 IPMP를 표준화하여 디지털 콘텐츠와 저작권에 대한 보호를 체계적이고 효과적으로 다루는 연구를 가장 활발히 해오고 있다. 이 논문에서 우리는 MPEG-4 콘텐츠 저작자가 MPEG-4 규격에 맞게 보호화 된 객체 기반 방송용 콘텐츠를 쉽고 편리하게 제작학 수 있도록 하기 위한 MPEG씨 콘텐츠 및 저자권 보호를 위한 MPEG-4 IPMP 저작 도구를 제안하고자 한다. 제안한 MPEG-4 콘텐츠 및 저작권 보호 저작 도구는 저작자에게 친근한 사용자 인터페이스를 제공하여 편집 및 수정이 용이한 텍스트 포맷인 IPMP회된 XMT(extensible Mpeg-4 Textual format) 파일을 생성한다. 또한, 콘텐츠 전송 및 저장의 효율성을 위해 이진 포멧인 IPMP화된 MP4 파일을 생성할 수 있다.으로써, 에러 이미지가 가지고 있는 엔트로피에 좀 근접하게 코딩을 할 수 있게 되었다. 이 방법은 실제로 Arithmetic Coder를 이용하는 다른 압축 방법에 그리고 적용할 수 있다. 실험 결과 압축효율은 JPEG-LS보다 약 $5\%$의 압축 성능 개선이 있었으며, CALIC과는 대등한 압축률을 보이며, 부호화/복호화 속도는 CALIC보다 우수한 것으로 나타났다.우 $23.87\%$($18.00\~30.91\%$), 갑폭 $23.99\%$($17.82\~30.48\%$), 체중 $91.51\%$($58.86\~129.14\%$)이였으며 성장율은 사육 온도구간별 차는 없었다.20 km 까지의 지점들(지점 2에서 지점 6)에서 매우 높은 값을 보이며 이는 조석작용으로 해수와 담수가 강제혼합되면서 표층퇴적물이 재부유하기 때문이라고 판단된다. 영양염류는 월별로 다소의 차이는 있으나, 대체적으로 지점 1과 2에서 가장 낮고, 상류로 갈수록 점차 증가하며 지점 7 상류역이 하류역에 비해 높은 농도이다. 월별로는 7월에 규산염, 용존무기태질소 및 암모니아의 농도가 가장 높은 반면에 용존산소포화도는 가장 낮다. 그러나 지점 14 상류역에서는 5월에 측정한 용존무기태질소, 암모니아, 인산염 및 COD 값이 7월보다 다소 높거나 비슷하다. 한편 영양염류와 COD값은 대체적으로 8월에 가장 낮으나 용존산소포화도는 가장 높다.출조건은 $100^{\circ}C$에서 1분간의 고온단시간 추출이 적합하였다. 증가를 나타내었는데, 저장기간에 따른 물성의 변화는 숭어에 비하여 붕장어가 적었다.양식산은 aspartic acid 및 proline이 많았다. 또한 잉어는 천연산이

• Journal of the Korea Academia-Industrial cooperation Society
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• v.16 no.6
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• pp.3736-3741
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• 2015

Crash impact test is conducted to verify the crashworthiness of fuel tank. Success of the crash impact test means the improvement of survivability of crews by preventing post-crash fire. But, there is a big risk of failure due to huge external load in the crash impact test. The failure of crash impact test can result in serious delay of a entire rotorcraft development because of the design complement and re-production of the test specimens requiring a long-term preparation. Thus, the numerical simulations of the crash impact test has been required at the early design stage to minimize the possibility of trial-and-error in the real test. Present study conducts on the numerical simulation of phase I crash impact test using SPH supported by crash simulation software, LS-DYNA. Test condition of MIL-DTL-27422 is reflected on analysis and material data is acquired by specimen test of fuel cell material. As a result, the crash load on the skin material, overlap area and metal fitting is estimated to confirm the possibility of acquisition of the design load for the determination of the overlap area and adhesive strength.

• Korean Journal of Materials Research
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• v.10 no.10
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• pp.703-708
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• 2000

As the engine design changes to get high efficiency and performance of commercial diesel engine, surface w wear of the earn follower becomes an important issue as applied load increasing at the contact face between cam follower and cam. We developed the ceramic cam follower made of sili$\infty$n nitride ceramic which was more wear resistant than the cast iron or sintered metal cam follower. Ceramic cam follower was made by direct brazing of thin ceramic disk to steel body using an active brazing alloy without the interlayer. In-situ crowning(R), resulted from the difference of thermal expansion coefficient between ceramic and carbon steel after direct brazing without any stress-relieving inter]ayer, could be controlled. When a earbon steel was heated above $A_{c1}$ point and then c$\infty$led, the expansion curve represented a hysteresis. Appropriate crowning was achieved below the $A_{c1}$ point(about $723^{\circ}C$) and crowning increased with brazing temperature exponentially above the $A_{c1}$ point. Optimum brazing temperature range was from 700 to $720^{\circ}C$. We developed successfully the ceramic cam follower having appropriate crowning and being inexpensive. Also we could successfully control the crowning of ceramic earn follower by hysteresis behavior of thermal expansion of earbon steel during direct brazing process.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.18 no.6
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• pp.459-463
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• 2017

Hot dip galvanizing in the steel plant is one of the most widely used methods for preventing the corrosion of steel materials including structures, steel sheets, and materials for industrial facilities. While hot dip galvanizing has the advantage of stability and economic feasibility, it has difficulty in repairing equipment and maintaining the facilities due to high-temperature oxidation caused by Zn Fume where molten zinc used in the open spaces. Currently, SM45C (carbon steel plate for mechanical structure, KS standard) is used for the equipment. If a part of the equipment is resistant to high temperature and Zn fume, it is expected to improve equipment life and performance. In this study, the manufactured Ni alloy was tested for its corrosion resistance against Zn fume when it was used in the hot dip galvanizing equipment in the steel plant. Two kinds of materials currently used in the equipment, new Ni alloy and Inconel(typical corrosion-resistant Ni alloy), were selected as the reference groups. Two kinds of molten metal were used to confirm the corrosion of each alloy according to the molten metal. Zn fume was generated by bubbling Ar gas from molten Zn in a furnace($500{\sim}700^{\circ}C$) and the samples were analyzed after 30 days. After 30 days, the specimens were taken out, the oxide layer on the surface was confirmed with an optical microscope and SEM, and the corrosion was confirmed using a potentiodynamic polarization test. Corrosion depends on the type of molten metal.

• Journal of Biomedical Engineering Research
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• v.40 no.5
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• pp.215-221
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• 2019

The respiratory medical device is a medical device that delivers optimal oxygen or a certain amount of humidification to a patient by delivering artificial respiration to a patient through a machine when the patient has lost the ability to breathe spontaneously. These include respirators for use in chronic obstructive pulmonary disease and anesthesia or emergency situations, and positive airway pressure devices for treating sleep apnea, and as the population of COPD (chronic obstructive pulmonary disease) and elderly people worldwide surge, the market for the respiratory medical devices it is getting bigger. As the demand for both airway pressure devices, there is a problem that the ventilator standard is applied because the reference standard has not been established. Therefore, the boundaries between the items are blurred due to the purpose, intended use, and method of use overlapping similar items in a respiratory medical device. In addition, for both airway pressure devices, there is a problem that the ventilator standard is applied because the reference standard has not been established. Therefore, in this study, we propose clear classification criteria for the respiratory medical devices according to the purpose, intended use, and method of use and provide safety and performance evaluation guidelines for those items to help quality control of the medical devices. And to contribute to the rapid regulating and improvement of public health. This study investigated the safety and performance test methods through the principles of the respiratory medical device, national and international standards, domestic and international licensing status, and related literature surveys. The results of this study are derived from the safety and performance test items in the individual ventilator(ISO 80601-2-72), the International Standard for positive airway pressure device (ISO 80601-2-70), The safety and performance of humidifiers (ISO 80601-2-74) and the safety evaluation items related to home healthcare environment (IEC 60601-1-11), In addition, after reviewing the guidelines drawn up through expert consultation bodies including manufacturers and importers, certified test inspection institutions, academia, etc., the final guidelines were established through revision and supplementation. Therefore, in this study, we propose guidelines for evaluating the safety and performance of the respiratory medical device in accordance with growing technology development.

• Journal of the Korean Society for Railway
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• v.16 no.3
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• pp.189-195
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• 2013

Recent trains have broadband train communication networks to improve train operation safety and to provide passengers with multimedia services. Compared to glass optical fiber, plastic optical fiber (POF) has a large diameter; it also provides the good durability and maintainability necessary to railway applications. This paper suggests an All-IP broadband train communication network that connects all devices in the train through a POF interface. Performance tests according to Korean railroad standards shows that this POF interface is usable in the range of vibration and temperature conditions encountered in trains. A dedicated Layer-2 switch with the POF interface is developed for the construction of the All-IP train communication network. A prototype 1Gbps train communication network was set up in a trial-run of train on a metro line using the developed Layer-2 switch and POF. On-track tests indicated the feasibility of the POF train communication network. POF has an additional advantage of economic feasibility, and it is expected to start a trend toward broadband train communication networks using POF.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.19 no.11
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• pp.96-104
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• 2018

Military vessels are complex weapon systems consisting of various integrated onboard equipment. Since their acquisition of military equipment takes a long period of time and a prototype ship is deployed and tested, vessel development has relied on its proprietary process. However, due to the growing complexity of onboard equipment technology, application of systems engineering (SE) process has become indispensable. Nonetheless, an effective design process complementing the existing design with the SE has not yet been developed. As such, we have studied an improved basic design process for submarines based on SE. To do so, we analyzed the processes for the basic design, technical review, and requirement management. Included reviews and requirements are SRR, SFR and PDR, and SSRS, SSS, and SSDD. By combining the results in the SE framework, we built an improved basic design process that can be applied in parallel with the SE-based technical review and requirement management. To assess the process, we applied our proposed model to the submarine development undergoing the basic design phase. It is possible to effectively manage the requirements, design artifacts and improve traceability, and also utilize them as test and evaluation materials. The SE-based basic design process is expected to be useful in other kinds of vessel design.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.22 no.2
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• pp.401-408
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• 2021

Supplies of wood chips for fuel tend to increase owing to energy decentralization and new renewable energy policies. This study suggests a technical method that is necessary in order to supply heating energy to rural regions by using wood chips for fuel. Therefore, this study investigates the effects of natural drying methods for eight months by installing a drying facility with natural ventilation capable of loading 10 tons of wood chips, and which derive a natural drying method based on this to meet the quality standards of wood chips for fuel. The study results confirm that it is possible to produce wood chips for high-quality fuel with water content at 20% or less after around 90 days of drying, provided that a drying facility with natural ventilation is equipped with materials that can be procured easily in rural regions. It is also possible to block the proliferation and fermentation of molds that affect the quality of wood chips, provided that intake and exhaust systems adhering to standards are equipped.

• Journal of the Korean Society of Marine Environment & Safety
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• v.28 no.4
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• pp.657-666
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• 2022

The International Maritime Organization(IMO) recommends the active implementation of national policies on technological development and energy efficiency to reduce Green House Gas (GHG) in the international shipping sector. Such IMO environmental regulation policies have a great impact on the entire shipping sector and are also a heavy burden on ship's owners. The most reasonable way to curb GHG emissions from ships comes down to the development of zero-emission ships. In other words, the development of a fuel cell ship (FCS) driven by an eco-friendly fuel is an alternative that can escape the IMO regulations. Countries in Asia, Northern America, and Europe independently develop and produce PEMFC, and are pursuing international standardization by acquiring approval in principle from an internationally accredited registration authority. Currently, there are three types of fuel cells (FC) that are recommended for ships: a Polymer Electrolyte Membrane Fuel Cell (PEMFC), a Molten Carbonate Fuel Cell (MCFC), and a Solid Oxide Fuel Cell (SOFC). In this study, PEMFC, which is expected to grow continuously in the global FC market, was analyzed domestic and international development trends, specifications, performance, and empirical cases applied to ships. In addition, when applying PEMFC to ships, it was intended to suggest matters to be considered and the development direction.

• Analytical Science and Technology
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• v.19 no.5
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• pp.369-375
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• 2006

Calibration gas mixtures were prepared using dynamic volumetric method according to ISO 6145-5 and the uncertainty was evaluated. Ten identical capillaries with 0.25 mm in inner diameter and 50 cm in length were applied in this system. Dilution ratio of parent gas was determined by the number of capillaries that passes parent gas and that passes balance gas through. Capillaries were made of Teflon which had good chemical stability against adsorption of gaseous substances. Mechanical valves were introduced in this system in order to minimize the thermal effect of solenoid valves. Concentration of prepared gases were compared with master grade standard gases in cylinders made by RiGAS Co. and calibration of the instrument were completed using comparison method according to ISO 6143. Experimental results showed that the coefficient of variance of diluted oxygen standard gases showed less then 0.2% in most dilution range, that of diluted hydrogen sulfide standard gases showed less then 1.0%. Therefore, it is proven that the standard gases prepared by this system are appropriate to be used as a calibration standards in ambient monitoring, etc.