• 한국철도학회:학술대회논문집
• /
• 한국철도학회 2005년도 춘계학술대회 논문집
• /
• pp.1125-1131
• /
• 2005

This study is based on the assumption of surface transport linkages between Korea and China. Active economic cooperation between South Korea and North Korea are expected within the near future and Russia and China have interested in the land transport linkages in Korean peninsula. How much freight demands between the two countries that has been mainly dependent on air and sea transportation so far may convert the transport mode to surface transportation are estimated. Particularly, freight demands between South Korea and China's three northeast provinces are focused. The sensitivity analysis depends on transport time and transport cost changes is included. The modal shifts is estimated to be more sensitive to the changes in transport costs than those in transport time, suggesting the importance of transport costs of rail and road. Despite the dearth of data on the surface transport operation in North Korea, the attempts made in this study to estimate the demand conversion are hope to provide reference points for potential effects of the rail and road transport connections between China and the Korea peninsula before our discussions expand to the establishment of freight transport network of the northest Asia and, moreover, the Eurasian continent.

• Structural Engineering and Mechanics
• /
• 제63권6호
• /
• pp.743-750
• /
• 2017

Modal parameter identification plays a key role in the structural health monitoring (SHM) for civil engineering. Eigensystem realization algorithm (ERA) is one of the most popular identification methods. However, the complex environment around civil structures can introduce the noises into the measurement from SHM system. The spurious modes would be generated due to the noises during ERA process, which are usually ignored and be recognized as physical modes. This paper proposes an improved stabilization diagram method in ERA to distinguish the spurious modes. First, it is proved that the ERA can be performed by any two Hankel matrices with one time step shift. The effect of noises on the eigenvalues of structure is illustrated when the choice of two Hankel matrices with one time step shift is different. Then, a moving data diagram is proposed to combine the traditional stabilization diagram to form the improved stabilization diagram method. The moving data diagram shows the mode variation along the different choice of Hankel matrices, which indicates whether the mode is spurious or not. The traditional stabilization diagram helps to determine the concerned truncated order before moving data diagram is implemented. Finally, the proposed method is proved through a numerical example. The results show that the proposed method can distinguish the spurious modes.

• 한국언어정보학회:학술대회논문집
• /
• 한국언어정보학회 2001년도 학술대회 논문집
• /
• pp.97-109
• /
• 2001

이 논문은 영어와 한국어에서 나타나는 완수동사(Accomplishment Verb)와 지속부사구(durative adverbial)의 상호작용에 대해서 논한다. Smith(1991)에 의하면 완수동사가 지속부사구와 결합하면, 동사와 부사구의 의미적 자질의 충돌을 피하기 위해서 완수동사의 상변환(Apsect Shift)이 일어난다. 본 논문은 이 상변환이 영어와 한국어에서 어떻게 실현되는가를 보이고, 이를 형식의미론에서 어떻게 기술할 수 있는가를 논한다. 완수동사가 지속부사구와 결합할 때, 영어와 한국어 모두에서 닫힌 완료 관점(closed perfective viewpoint)에서 열린 관점(open viewpoint)으로 관점 변환(viewpoint shift)이 일어난다. 그러나, 한국어의 상변환과 영어의 상변환이 완전히 일치하는 것은 아니다. 한국어의 관점변환은 완료관점도 아니고 미완료 관점도 아닌, 중립관점(neutral viewpoint)으로의 변환인 반면, 영어의 관점변환은 단순히 미완료 관점으로의 변환임이 논의된다. 이 주장은 한국어의 관점변환 구문은 이질적인 다수 사건의 연속 해석(heterogeneous sequential reading of multiple events)을 허용하는 반면, 영어의 관점변환구문은 오직 동질적인 단일 사건의 동시 해석 (homogeneous simultaneous reading of a single event)만을 허용한다는 사실에 의해서 지지 된다. 본 논문은 완수동사가 지속부사구와 결합할 때 일어나는 상변환에 대한 형식의 미론 분석을 Heim ＆ Kratzer (1998)의 틀에서 제시한다. 닫힌 관점에서 열린 관점으로의 상변환은 비가시적 시제 서법 운용자(covert temporal-modal operator)인 IMP를 지속부사구의 논항으로 설정하여 설명한다. IMP는 Dowty (1979)에서 미완료상의 모순(imperfective paradox)을 해결하기 위해서 설정한 PROG를 Heim ＆ Kratzer (1998)의 틀에 맞게 수정한 것이다. IMP는 평가 세계 (evaluation world)를 현실 세계(actual world)에서 가상 관성 세계(possible inertia would)로 변화시켜서, 완수동사의 종결점(ending point)을 현실세계에서 가상의 미래 세계로 움직이는 역할을 한다. 결과적으로, IMP는 완수동사의 닫힌 완료 관점을 현실세계에서는 열린 미완료 관점으로 변환시키되, 가상 관성 세계에서는 그대로 닫힌 관점으로 유지 시키는 효과를 가진다. 한국어와 영어의 관점 변환 구문의 차이는 각 언어의 지속부사구의 어휘 목록의 전제(presupposition)의 차이로 설명된다. 본 논문은 영어의 지속부사구는 논항의 하위간격

• 한국철도학회:학술대회논문집
• /
• 한국철도학회 2011년도 정기총회 및 추계학술대회 논문집
• /
• pp.2949-2951
• /
• 2011

It is expected that domestic railway vehicle operation companies may be subjected to GHG emission reduction when GHG emission system is enforced. This study aimed that reviewing on GHG emission system such as CDM, VCS and KCER, and analysing availability of GHG emission credit acquisition for railroad transportation sector. In order to estimate GHG emission credit, a GHG emission estimation methodology should be developed, which includes GHG emission baseline estimation and GHG emission monitoring method, MRV method and etc. Modal shift project, high speed train technology, straight lining project, mass transportation technology, operation optimization tehcnology and etc. may produce GHG emission credit.

• 한국소음진동공학회:학술대회논문집
• /
• 한국소음진동공학회 2007년도 추계학술대회논문집
• /
• pp.693-696
• /
• 2007

In this paper, vibration sources of an electric forklift are identified and the forklift vibrations are reduced by structural modification by using the finite element analysis. From some experiments, it is also found that resonances occur because the natural frequencies of the forklift exist in usual driving speed range. To vibration sources of the electric forklift, the modeling is designed by using a commercial 3D CAD program CATIA and the finite element model is designed by a using finite element analysis program ANSYS which can perform modal analysis of flexible mode. To shift the natural frequencies out side the driving speed range, the frame part, the connection parts between main body and loader are modified to increase stiffness. It is verified that considerable amount of vibration are reduced by the structural modification.

• 한국소음진동공학회:학술대회논문집
• /
• 한국소음진동공학회 2008년도 추계학술대회논문집
• /
• pp.641-645
• /
• 2008

In this paper, vibration sources of the BLOC motor are identified and the motor vibrations are reduced by structural modification. For vibration characteristic identification, vibration signals measured by an accelerometer when the BLOC motor is moving. These signals are presented in a waterfall plot in order to find the dependency of frequency components on the motor speed. It is found that main vibration source is BLOC motor test rig. From finite element analyses and some experiments, it is also found that resonances occur because the natural frequencies of the test rig exist in usual driving speed rang. To shift the natural frequencies outside the driving rang, the test rig is modified increase stiffness. It is verified that considerable amount of vibration are reduced by the structural modification.

• 한국소음진동공학회:학술대회논문집
• /
• 한국소음진동공학회 2008년도 춘계학술대회논문집
• /
• pp.144-149
• /
• 2008

In this paper, vibration sources of a car-holder are identified and the car vibrations are reduced by structural modification. For vibration identification, vibration signals are measured by an accelerometer when the car is moving. From some experiments and finite element analyses, it is also found that resonances occur because the natural frequencies of the car exist in usual driving speed range. To shift the natural frequencies outside the driving speed range, the connection part is modified to increase stiffness. It is verified that considerable amount of vibration are reduced by the structural modification.

• 무역상무연구
• /
• 제40권
• /
• pp.147-167
• /
• 2008

This paper investigates changing business transaction under the e-commerce environment and their implications on freight transport industry with some case studies. It shows that an efficient and reliable delivery system is essential for e-commerce as business industries are faced with the stricter and more diversified demands of customer. In addition, many aspects of business practices such as small batch, customized production and just-in-time distribution in the e-commerce environment, in turn, bring about a number of changes in the volume and service patterns of freight transport. E-commerce requires longer transport distances and often higher delivery frequencies. It also entails to a certain extent a modal shift towards truck and air freight transport modes. On the one hand, the logistical requirements of e-commerce goods may stimulate greater complexity in existing supply chain management, causing higher costs. However it is true that the increased visibility of goods through more efficient information flow allows more efficient and effective transport management in the logistics system.

• 대한기계학회논문집A
• /
• 제20권1호
• /
• pp.1-13
• /
• 1996

The measurement of radial directional natural frequency ina passenger car tire rotating under the load is studied. In order to obtain theoretical matural frequency and mode shape, the ploane vibration of a tire is modeled to that of circular beam. By esing the Tieking method based on Hamiltons's principle, theoretical results are determined by considering tension horce due to tire inflation pressure, retational velocity and tangential, radial stiffness. Radial directional modal parameters varying with the inflation pressure, load, rotational velocity are experimentally determined by using frequency response function method. The results show that experimental conditions canbe considered as the parameters which shift the natural frequency.

• 한국자동차공학회논문집
• /
• 제5권3호
• /
• pp.66-75
• /
• 1997

Sound transmission from the luggage comparment into the car cabin is important in the viewpoint if exhaust and road noises of passenger cars. In this paper, acoustic modal coupling between passenger and luggage compartments through loudspeaker holes at parcel shelf is dealt with for a sedan type passenger car with rigid rear seat. For these purposes, a half-scaled model car is tested and computed by the indirect BEM. Predicted acoustic transfer functions are compared with experimental ones and they agree reasonably well. It is found that the fore-aft resonance frequencies of the passenger cavity in the absence of coupling holes are tend to shift to higher frequencies when the luggage compartment is coupled to the passenger cavity.