• 산업진흥연구
• /
• 제8권3호
• /
• pp.9-17
• /
• 2023

본 연구의 목적은 주요 여객수단인 철도, 지하철, 국내해운, 국내항공, 국제해운, 국제항공의 동향과 변동률을 분석하는데 있다. 사용된 자료는 통계청 국가통계포털 "국내통계, 주제별통계, 교통.물류"에서 자료를 선택하였다. 분석 기간은 1999년부터 2020년까지 총 22년간이며 전년대비 연간 변동률을 산출하였다. 기술통계량에서 국제해운과 국제항공은 상대적으로 변동성이 크게 나타난 반면 철도와 지하철은 작게 나타났다. 상승률 분석에서 국제항공과 국제해운은 2019년도 539%와 368%에서 코로나로 인해 2020년에 85%와 20%로 크게 하락하였다. 국제항공과 국제해운은 2020년에 크게 하락하였으나 코로나의 충격이 사라지면서 다시 상승할 것으로 기대하면서 이에 대비하는 전략이 필요할 것으로 보인다. 국제 무역이 다시 증가하고 해외여행이 다시 활력을 찾아가면서 기존의 상승세가 계속 이어질 것으로 예상해 본다.

• 환경영향평가
• /
• 제7권1호
• /
• pp.109-116
• /
• 1998

As of July 1997, the registered number of automobiles exceeded 10 million and Korean auto industry produced 2,850,000 cars. Many environmentalists warn that the passenger cars are not sustainable urban transportation system in large cities. The cars produce about 80% of air pollutants, and consume 30% of petroleum imported. For the past 30 years the administration increased the road system, but the length of road per car is decreased from 813m in 1965 to 9m in 1995. The cost of traffic congestion was estimated to be \14.7 trillion in 1996, and is feared to increase without changing the present transportation system. The undesirable impact of cars include the casualties from traffic accidents, insurance loss, and separation of human relatioships. To construct sustainable urban transportation system, three principles should be followed. The first principle is to make the urban streets walkable for the people. The second principle is to encourage bicycling. Roads and traffic systems should be designed to let bicylces travel safely. The third principle is to supply more buses and construct integrated transportation system based on buses. The subway system is too expensive to construct and without the support of a well-organized bus system it may not work efficiently. The Brazilian city of Curitiba has constructed a very efficient bus system only with 1/80 of the estimated cost of subway system. The car-oriented transportation system does not seem to be an envrironmentally sustainable transportation system in most of the Korean cities.

• 한국소음진동공학회:학술대회논문집
• /
• 한국소음진동공학회 2007년도 추계학술대회논문집
• /
• pp.488-492
• /
• 2007

Since Equipment-Noises occurring in machine room penetrate wall-body and travel to the adjacent room in the form of air-borne sound and structure-borne sound, it is appearing as the main factor that injures a peaceful residential environment, and due to this, such noise-damage is currently increasing rapidly. Consequently, despite the measures for sound-insulation and soundproof against the equipment-noise penetrated wall-body is urgently required, but as the subjective evaluation considered for psychological response about the equipment-noise was not practiced, many dissatisfactions are still raising even after some measure was taken. On such point of view, this Research, at the spot, has actually measured the equipment-noise that had permeated various wall-bodies, and examined its physical characteristics, thence based upon this, has conducted Psycho-Acoustics Experiment and investigated the interrelation between the physical evaluation value and psychological reaction value. It is considered that such study result could be utilized as the useful material at the time of establishment of the Grading Standard for the insulation performance against the Architectural Plumbing Noise, in the future.

• 한국정보과학회:학술대회논문집
• /
• 한국정보과학회 2007년도 한국컴퓨터종합학술대회논문집 Vol.34 No.1 (C)
• /
• pp.204-208
• /
• 2007

대화시스템은 사용자가 자연언어를 사용하여 해당 시스템과 필요한 정보를 주고받는 목적 지향적 에이전트로서 활용되어 왔다. 이러한 대화형 에이전트는 사용자의 입력으로부터 필요한 정보를 정확하게 추출함으로써 이후 처리단계에서의 결과를 향상시킬 수 있다. 본 논문에서는 항공여행관련 대화에서 발생하는 예약정보들 중에서 경유정보, 특히 경유하는 시간 및 날짜에 대한 정보를 효과적으로 추출하는 방법에 대해서 다룬다. 출발 도착정보와 경유정보를 계층적으로 분류하고, 현재 발화되고 있는 문장보다 선행되고 있는 문장들의 예약정보들을 문맥정보로 사용하여 현재 문장에서 추출하고자 하는 정보들을 학습하고 평가하였다. 이를 통해서 얻어진 결과는 출발.도착 및 경유정보를 동시에 고려했을 때보다 효과적인 학습 성능을 보였으며 실제로 시간정보에 대해서는 81.5%, 날짜정보에 대해서는 92.0%의 정확도를 보였다.

• 동력기계공학회지
• /
• 제10권3호
• /
• pp.11-16
• /
• 2006

The pressure fluctuation in the intake and exhaust pipe of 4 stroke-cycle diesel engine is caused by reciprocating motion of piston for suction of fresh air and exhaust of burned gas. this gas dynamic effect can be utilized for increase the volumetric efficiency. Many empirical studies have been carried out to investigate the effects of intake pulsating flow on the volumetric efficiency. However, when the gas dynamic effects are utilized for the variable speed engine to increase its performance, The speed range in which the maximum volumetric efficiency is limited and there occurs some difficulties in lay-out of intake system because it become too long. During induction process, as waves travel both directions, they are reflected and interacted each other and pressure waves are transmitted through it. Hence, the flow becomes more complex and unsteady flow. These pressure waves act upon intake pulsating flow and affects on the volumetric efficiency. In this paper the effects of pulsating flow of intake and exhaust pipes on volumetric efficiency were examined and evaluated. It was found that volumetric efficiency was affected by pulsating flow of intake and exhaust pipes.

• 한국항공운항학회지
• /
• 제26권3호
• /
• pp.93-104
• /
• 2018

It is mandatory to use car seats for infants and children in the private vehicles in accordance with the traffic law of Korea. Recently, legislation has also been proposed to expand the use car seats to express and intercity buses. This reflects a growing consensus that mandatory infant and child car seats, both for private and commercial vehicles, are essential. However, Korean laws concerning infants and children on board aircraft allow parents or guardians to hold children under two years of age on their laps without any restraint devices. It is not possible for a parent to physically restrain an infant or child, especially during a sudden acceleration or deceleration, unanticipated or severe turbulence, or impact. The use of CRS provides an equivalent level of safety to infants and children as that afforded to adult passengers wearing seat belts. But there is no regulation even about Child Restraint Systems on board aircraft in Korea. To enhance their safety, infants and children should be restrained in an approved child restraint system that is appropriate to their weight and height. It is necessary to examine whether infants and children in flight can achieve the same level of safety as an adult.

• The Journal of Asian Finance, Economics and Business
• /
• 제7권3호
• /
• pp.201-210
• /
• 2020

The study aims to investigate determinants of performance indicator and perceptions of existing and potential customers in accommodation sharing. This study uses data of Airbnb in Busan and Jeju from January 1 to December 31 in 2018, provided by AirDNA. The total number of listed accommodation sharing were 5,109 accommodations in Busan and 11,502 accommodations in Jeju. More than 90 property types of registered accommodation are subcategorized and re-classified in this study. Study 1 examined current usage and effects of factors on performance indicator in tourism destinations by applying Airbnb data. Study 2 investigated effects of perceived factors on satisfaction, intention to use, loyalty, and tourism competitiveness by applying online survey data. This study applies statistical analyses such as factor and regression analyses, ANOVA, t-test, and MANOVA. Results of Study 1 showed that usage and effects of accommodation sharing differ from regulation that is related to sharing types. Effects also differ based on travel destinations. Results of Study 2 showed how customers perceive accommodation sharing differ from pure meaning of sharing. The results of Study 1 and 2 found significant effects of price and service factors on performance indicator and customer satisfaction. The findings of Study 2 showed significant effects on loyalty and tourism competitiveness.

• 제어로봇시스템학회:학술대회논문집
• /
• 제어로봇시스템학회 1992년도 한국자동제어학술회의논문집(국제학술편); KOEX, Seoul; 19-21 Oct. 1992
• /
• pp.340-343
• /
• 1992

Fundamental positioning characteristics of a dual-axis Sawyer linear motor are described. The Sawyer motor is capable of high positional accuracy. An electronic control unit of the motor whose velocity is proportional to the frequency of the electric current was produced in our laboratory. The positioning system was constructed using two Sawyer motors, an air bearings suspension unit and an electronic control unit. The stable motion of the motor was confirmed on the open loop operation. The adjustable operating conditions were the live load of 1 kg, the maximum acceleration of 1.2G and the maximum velocity of 350 mm/s. Absolute positioning accuracy was improved within .+-.5.mu.m, on microstep operating conditions of dividing one pitch of 508.mu.m into 508 steps. The following two conclusions were obtained. An accelerating-cruising-decelerating control is effective for reduction in the travel time required. Also, microstep operation is effective for improving the resolution of position.

• Journal of Magnetics
• /
• 제19권3호
• /
• pp.300-308
• /
• 2014

This paper develops a moving-magnet electromagnetic actuator for fast steering mirror (FSM). The actuator achieves a reasonable compromise between voice coil actuator and piezoelectric actuator. The stroke of the actuator is between the strokes of a piezoelectric actuator and a voice coil actuator, and its force output is a linear function of air gap and excitation current within our FSM travel range. Additionally, the actuator is more reliable than voice coil actuator as the electrical connection in the actuator is static. Analytically modeling the actuator is difficult and time-consuming. Alternatively, numerous finite element simulations are carried out for the actuator analysis and design. According to the design results, a real prototype of the actuator is fabricated. An experimental test system is then built. Using the test system, the force output of the fabricated actuator is evaluated. The test results validate the actuator analysis and design.

• 한국철도학회:학술대회논문집
• /
• 한국철도학회 2009년도 춘계학술대회 논문집
• /
• pp.1454-1460
• /
• 2009

Ultra-speed tube train, which runs in vacuum atmosphere to overcome aero-dynamic dragging force, is considered as a high-speed ground transportation system to back up long-distance air travel. To realize the ultra-speed tube train, feasibility study of currently available Maglev technologies especially for propulsion and levitation system is needed. Propulsion by linear synchronous motor(LSM) and levitation by electro-dynamic suspension(EDS) which are utilized in the Japan's MLX system could be one of candidated technologies for ultra-speed tube train. In the LSM-EDS system, the key component is superconducting magnet, and its reliability and performance is very important to guarantee the safe-operation of Maglev. As the initiative of the feasibility study, this paper deals with the basic structure of superconducting magnet and core technologies to design and operate it. And by surveying the current R&D achievement in Korea, the nation's capability to develop advanced superconducting magnet for Maglev is presented.