• KIPS Transactions on Software and Data Engineering
• /
• v.6 no.10
• /
• pp.473-478
• /
• 2017

Drones require altitude holding in order to achieve flight objectives. The altitude holding of the drone is to repeat the operation of raising or lowering the drone according to the altitude information being measured in real-time. When the drones are maintained altitude, the drone's altitude will continue to change due to external factors such as imbalance in thrust due to difference in motor speed or wind. Therefore, in order to maintain the altitude of drone, we have to exactly measure the continuously changing altitude of the drone. Generally, the acceleration sensor is used for measuring the height of the drones. In this method, there is a problem that the measured value due to the integration error accumulates, and the drone's vibration is recognized by the altitude change. To solve the difficulty of the altitude measurement, commercial drones and existing studies are used for altitude measurement together with acceleration sensors by adding other sensors. However, most of the additional sensors have a limitation on the measurement distance and when the sensors are used together, the calculation processing of the sensor values increases and the altitude measurement speed is delayed. Therefore, it is necessary to accurately measure the altitude of the drone without considering additional sensors or devices. In this paper, we propose a measurement algorithm that improves general altitude measurement method using acceleration sensor and show that accuracy of altitude holding and altitude measurement is improved as a result of applying this algorithm.

• The Korean Journal of Air & Space Law and Policy
• /
• v.35 no.2
• /
• pp.225-246
• /
• 2020

More than technical or academic matter, mitigation of height restriction around airports is about up-dating out-dated policies that have not kept up with rapidly developing aircraft and air traffic control technologies. Above all, instead of calling out 'flight safety' that the public do not comprehend, it is important to examine and carry out measures that can protect people's right of property. MOLIT(Ministry of Land, Infrastructure, and Transport) after reviewing ICAO's Obstacle Limitation Surface TF, made an announcement to provide further plans that would apply to contracting states from 2026. However, residents of redevelopment areas near Kimpo international airport asserted that MOLIT's policy overlooks the reality of the redevelopment zone. ICAO, UN's specialized agency for civilian aviation, recommends in Annex 14, 4.2.4 that contracting states conduct an aeronautical study to determine the flight safety of horizontal surface(45m), excluding approach surface, and to mitigate height restrictions if no threat is found. Numerous countries including the United States have been following this recommendation and have been able to effectively protect people's right of property, whereas the South Korean government have not following it so far. The number of height restriction mitigation cases in the recent three months (2019. 7. 15~10. 14.) FAA of the United States have allowed after conducting an aeronautical study reaches 14,706. Japan and Taiwan also reconstruct airspace around airports in metropolitan areas in order to protect people's right of property. Just as the United States is following, MLIT should follow ICAO's recommendation in Annex 14. 4.2.4(Vol. 1. Airport Construction / Operation) and protect people's right of property by first applying aeronautical studies to the horizontal surface(45m) of flight safety zones until the specifics of ICAO's 2026 TF materialize.

• Journal of the Korean Institute of Gas
• /
• v.14 no.1
• /
• pp.21-27
• /
• 2010

In the past vaporized gases from a carrier were burned or used for fuel. Due to the movement of bigger LNG carriers and using diesel engine, it is limited that ways of deposing vaporizes gases from the carrier by the act of environment. For getting over the problem, a reliquefaction process is considered. Even though the reliquefaction process was created to three generation process, it has been researched and developed to optimize the process. Basically the reliquefaction process is compartmentalized into Reverse Brayton Cycle System and Claude Cycle System. This research is focused on the reliquefaction efficiency with the systems and changing equipments arrangement by using HYSYS. The result could be use for a design of a reliquefaction process.

• Journal of Korea Multimedia Society
• /
• v.10 no.8
• /
• pp.958-966
• /
• 2007

In this paper, we implement a sound-enhanced MPEG-1 audio decoder on embedded OS Platform. Low bit rate lossy audio codecs such as MP3, OGG, and AAC for mitigating the problems in storage space and network bandwidth suffer a major common problem such as a loss of high frequency fidelity of audio signal. This high frequency loss will reproduce only a band-limited low-frequency part of audio in the standard CD-quality audio. In order to overcome this problem, we embedded a sound enhancement algorithm into the MPEG-1 audio decoder and then the algorithms optimized according to the characteristic of the MPEG-1 audio layer I, II, III were implemented on an embedded OS platform. From the experimental results with spectrum analysis and listening test, we confirm the superiority of the proposed system compared to the standard MPEG-1 audio decoder.

• Journal of the Korean Institute of Telematics and Electronics S
• /
• v.36S no.12
• /
• pp.34-40
• /
• 1999

In conventional color television systems color edges of highly saturated color pictures are deteriorated because of bandwidth limitation of the color-difference signal. In this paper a modified hue-weighted luminance demodulation method with low noise is proposed for the edge correction. The weighting coefficients are given by ratios of the gadient of color-difference signal to the gradient of band-limited luminance signal. Proposed method is theoretically complete for the 1st order lowpassed color-difference signals and well separated luminance/chrominance signal. Noise reduction technique is also considered because of impulse noise generation in the gradient ratio processing of noisy pictures. In computer simulation with noisy pictures proposed technique gives a visual effect of the bandwidth expansion and detail improvement in highly saturated color edge area.

• Journal of Nuclear Fuel Cycle and Waste Technology(JNFCWT)
• /
• v.7 no.3
• /
• pp.183-190
• /
• 2009

The basic function of HLW disposal system is to prevent excessive radio-nuclides being leaked from the repository in a short time. To do this, many technical standards should be developed and established on the components of disposal system. Safety assessment of a repository is considered as one of technical standards, because it produces quantitative results of the future evolution of a repository based on a reasonably simplified model. In this paper, we investigated other countries' regulations related to safely assessment focused on the assessment period, radiation dose limits and uncertainties of the assessment. Especially, in the investigation process of the USA regulations, the USA regulatory bodies' approach to assessment period and peak dose is worth taking into account in case of a conflict between peak dose from safety assessment and limited value in regulation.

• Journal of the Korean Society of Marine Environment & Safety
• /
• v.13 no.1 s.28
• /
• pp.55-60
• /
• 2007

Many electric power cables span the sea in Korean archipelago. Lots of shipping routes were established between the islands in the same area and ships frequently sail under the cable which cross the seas. Sometimes electric power cables were accidently broken by sailing ships and catastrophic damage of island industry followed thereby. If navigators have detailed knowledge about the height of electric power cable, the ship's sailing condition will be greatly improved. But at the present time, navigators have limited data about the electric power cable. Those are the horizontal distance between pylons, the height of pylons and minimum height of electric power cable. This study introduced the calculating methodology to find out the height of cable at any position between pylons. The ship's tracks were recorded and traffic safety was assessed by statistical method in relation to cable height.

• The Bulletin of The Korean Astronomical Society
• /
• v.37 no.2
• /
• pp.163.1-163.1
• /
• 2012

이 연구는 우주물체에 대한 광학감시 및 추적을 수행하기 위한 선행연구로, 궤도전파 시뮬레이터를 개발하여 궤도상 위성의 광학관측가능성을 분석하고 광학관측 여부를 판단하는 것을 목표로 한다. 연구의 주 내용은 주어진 궤도정보를 바탕으로 하는 태양동기궤도(Sun-Synchronous Orbit; SSO) 위성, Dawn-dusk 위성, 저궤도(Low Earth Orbit; LEO) 위성, 정지궤도(Geostationary Orbit; GEO) 위성 등 궤도상 위성의 추정궤도 전파와 자국위성의 광학관측가능성 분석으로 구성된다. 각각의 궤도전파 정밀도 및 광학관측가능성 분석성능을 확인하기 위해 AGI(Analytical Graphics Incorporated)사의 STK(Satellite Tool Kit) 시뮬레이션 프로그램을 사용하여 개발된 궤도전파 시뮬레이터와 비교하였다. 시뮬레이션 과정에서 광학관측의 제한조건을, 지구반영(penumbra)과 태양직사광(direct sun)에서만 관측하며, 고도(elevation angle)의 최소값은 20도, 태양고도(Sun elevation angle)의 최대값은 -10도로 설정하였다. 광학관측이 이루어지는 가상의 관측소는 임의로 선정하였으며, 기본적인 관측시간은 1년으로 잡고, 계절의 변화에 따른 광학관측가능성 궤적의 변화를 보기위해 춘하추동에 대해서 각각 3일이내의 기간 동안 시뮬레이션을 수행하였다. 결과적으로, 우주물체 광학감시 및 추적을 수행하기 위한 광학관측가능성 분석성능은 궤도전파 시뮬레이터 및 초기궤도요소 정밀도, 좌표변환과정 오차 등의 영향을 받으며, 설정된 제한조건에 따라 광학관측 지속시간의 차이가 발생한다. 연구결과를 통해 궤도상 위성의 궤도를 추정하기 위한 위성의 궤도전파 시뮬레이터를 개발하고, 자국위성의 관측가능성 분석을 통해 광학감시 및 추적시스템의 운영이 원활히 이루어질 수 있도록 한다.

• Journal of the Korea Society of Computer and Information
• /
• v.17 no.1
• /
• pp.31-40
• /
• 2012

u-GIS DSMSs have been researched to deal with various sensor data from GeoSensors in ubiquitous environment. Also, they has been more important for high availability. The data from GeoSensors have some characteristics that increase explosively. This characteristic could lead memory overflow and data loss. To solve the problem, various load shedding methods have been researched. Traditional methods drop the overloaded tuples according to a particular criteria in a single server. Tuple deletion sensitive queries such as aggregation is hard to satisfy accuracy. In this paper a dual processing load shedding method is suggested to improve the accuracy of aggregation in clustering environment. In this method two nodes use replicated stream data for high availability. They process a stream in two nodes by using a characteristic they share stream data. Stream data are synchronized between them with a window as a unit. Then, processed results are merged. We gain improved query accuracy without data loss.

• Journal of Korea Fair Competition Federation
• /
• no.26
• /
• pp.34-45
• /
• 1997

세계 경제질서의 급속한 변화에 따라 최근에 많은 선진국들이 경쟁법을 개정하거나 앞으로 개정할 움직임을 활발히 전개하고 있다. 특히 이중에서 글로벌 경제의 급속한 진전에 따라 여기에 대응하기 위한 경쟁법의 개정 움직임도 활발하게 이루어지고 있음을 음미해보아야 할 것이다. 미국은 반트러스트법의 개정을 검토하기 위하여 공청회를 개최하고 ''95년 5월 ''새로운 하이테크 글로벌 시장에서의 경쟁정책''이라는 보고서를 발표하였으며, 이에 따라 합병심사에서 효율성을 앞세워 미국 국내기업의 해외 진출을 지원하고 합병을 용이하게 하도록 ''92년에 제정된 합병 가이드라인을 개정하였다. EU의 구주위원회도 기업결합의 글로벌화가 촉진되도록 ''96년 7월 합병규제규칙을 개정하여 업계가 손쉽게 합병을 할 수 있도록 절차에 있어 일원적 처리의 범위를 확대하였으며, 기업의 규제대상이 되는 연간 매상고기준을 인하하고 합병심사의 대상기업이라도 경쟁상 중대한 문제가 발생하지 않는 것으로 판단되면 공동체 시장에서 적합성을 선언할 수 있도록 하고, 경쟁제한법 협정의 적용제외 규정에서 수직적 제한에 대한 경쟁법 적용여부의 결정은 당사자의 시장점유율을 고려해서 적용여부를 결정하는 등 폭넓은 선택이 가능하도록 개정하였다. 이에 따라 EU국가인 독일, 영국, 프랑스 등의 EU회원국들은 EU합병규제규칙 및 EU경쟁법과의 조화가 이루어지도록 자국의 법체계를 정비하고 있다. 이에 따라 독일은 지난 ''97년 7월 31일에 경쟁제한금지법 제정 이후 40년만에 근본적인 개정의 필요에 따라 EU경쟁법과의 조화, 카르텔에서 적용제외 규정을 글로벌 경제구조에 맞도록 과감히 삭제$\cdot$축소하고, 합병규제대상의 매상고기준을 상향(5억$\right$10억마르크)하고 법체계를 명확하고 알기 쉽게 정리하는 개정(안)을 발표한 바 있다. 그리고 영국 무역산업성 장관은 지난 ''97년 8월 7일 영국의 경쟁법개정(안)을 금년 가을까지 성립을 목표로 발표하였는데, 그 주요 내용은 반경쟁적 협정 및 시장지배력 남용에 대한 강력한 억제력과 중대한 남용행위에 제재금을 부과함으로써 경쟁을 통한 소비자의 이익과 선택을 확보하고 산업계의 불필요한 부담을 경감토록 하여 글로벌시장 경쟁에서 혁신과 투자를 자극하도록 유도하였고, 프랑스는 생산업자와 유통업자에 의한 부당염매금지 제도를 도입하고 경쟁제한행위금지 위반시의 벌칙을 강화했다. 일본은 치열한 국제경쟁에 대응하고 경제구조의 개혁과 사업자활동을 보다 촉진하기 위하여 지난 1997년 6월 11일 일본독점금지법을 개정하여 독점금지법에 위배되지 않는 범위에서 지주회사 설립 금지를 해체하고 대규모회사 주식보유총액제한 규제대상을 완화하는 한편 국제계약신고제도를 폐지하였다. 캐나다는 합병신청서 제출기간을 연장하고 통신판매를 직접규제대상으로 경쟁법 개정을 준비하였고, 호주는 거래관행법을 개정하여 연방정부와 주$\cdot$준주 정부간의 경쟁정책의 법적용을 통일하고 거래관행법 적용을 모든 사업에 확대하며, 재판매가격유지행위의 금지대상에 용역(전기통신서비스)도 포함시키고 시장참입을 촉진하는 제도를 신설하였다. 뉴질랜드는 합병이 국내시장에 영향을 주는 경우에는 외국에서의 합병에도 경쟁법을 확대적용하도록 하였다. 위와 같이 세계의 많은 국가에서 경쟁정책에 대한 새로운 동향과 공정거래법에 대한 개정작업이 활발히 이루어지고 있는데, 본고는 미국, EU, 독일, 영국, 프랑스, 일본, 캐나다 및 호주와 뉴질랜드 등 주요선진국에서의 공정거래법 개정 동향에 대한 주요 내용을 소개한 것이다.