• IE interfaces
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• v.13 no.3
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• pp.471-478
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• 2000

One of the most important problems encountered by parcel transportation firms or LTL (Less-than-truckload) firms is the planning of daily linehaul operations. The transportation firm's goal is to determine the most efficient way to move all freight from its originating terminal to its destination terminal after each shipment is picked up from the shipping dock. The purpose of this study is to design a transportation system and develop an efficient scheduling algorithm for linehaul operations carrying small amount of shipment. This paper presents three approaches for efficient linehaul operations. The first approach examines drivers using the roundtrips which start from a terminal, visit several terminals, and return to the starting terminal. The second approach uses a freight assembly center where drivers take freight for a number of destination terminals which they then swap for freight for their starting terminal. The third approach is similar to the second approach in that it uses a transshipment point like a freight assembly terminal for shipment, but it has several transshipment points since each shipment may have a different transshipment point. In this study, we developed a mathematical formulation and algorithm for each approach. The experimental results using data of a LTL firm show that the third approach is more efficient than the other two. Mileage and overnight stays of the third approach are reduced by 10% and 30%, respectively.

• Journal of the Korean GEO-environmental Society
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• v.16 no.2
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• pp.15-25
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• 2015

As the physical and mechanical properties of lightweight air-mixed soil change in the procedure of transportation of mix truck, it is necessary to assure whether the properties during construction satisfy those in design. In this study, variations of properties of mixed soil after transportation by mix truck are proved by field test. Lightweight air-mixed soil used field test the unit weight of $9.0{\pm}1.0kN/m^3$, the flow value of $190{\pm}20mm$ was produced. To analyze variations of properties of mixed soil the unit weight and flow value of the sample before and after transport was measured unconfined compressive strength tests were performed. Mixing time was 19~175 minutes diversified. As the test results, it is known that the density, the flow value and the unconfined compressive strength of lightweight air-mixed soil change by transportation, but these values satisfy the specifications of material of air-mixed soil. After transportation the average value of the unit weight and flow value change in the flow of the $(+)0.10kN/m^3$, 4.8 mm respectively, the average change in the unit weight and the flow value due to the mixing time was constant. And unconfined compressive strength of 28-day specimen increases from 20 to $150kN/m^2$. But, these values do not have some clear relationship with the transportation time within 175 minutes which is longest test time. Consequently, Within 175 minutes the changes of properties by transportation are too small to show some problems in the construction field.

• Tribology and Lubricants
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• v.29 no.5
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• pp.291-297
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• 2013

Hydraulic directional control valves actuated by solenoid are used to control emergency steering in general or hybrid electric commercial vehicles. In this study, a new lightweight hydraulic directional control valve was designed by flow and structural simulation, and was fabricated; the basic operation, pressure differentials, and inner leakage flow were evaluated experimentally. In the results, the new model showed comparable performance with an existing imported valve. New valve was 80% the weight of the existing valve and had few components. Installing this valve on a truck body is easier because of its compactness and small size.

• Proceedings of the Korea Concrete Institute Conference
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• 2002.10a
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• pp.717-723
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• 2002

Recently, the interest in safety assessment of civil infrastructures is increasing in Korea. Especially, as bridge structures become large-scale, it is necessary to monitor and maintain the safety state of bridges, which requires the monitoring system that can make a long-term measurement during the service time of bridge. In this paper, advanced fiber optic sensors for long-term measurement, setup techniques of bridge monitoring system and the assessment of measured data are introduced. Attached or embedded optical fiber sensors to structural members of small and big structures including Sung San Bridge are surveyed. For the Sung San Bridge, the responses of the fiber optic sensors by 30 ton weigh truck loads with various speeds ate measured. Monitoring system is also applied to the mock-up of bridges. The monitoring capability of the advanced fiber optic sensor system was confirmed.

• Journal of Korean Institute of Industrial Engineers
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• v.35 no.1
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• pp.1-14
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• 2009

The efficiency of transportation requests fulfillment can be increased through extending the problem of vehicle routing and scheduling by the possibility of subcontracting a part of the requests to external carriers. This problem extension transforms the usual vehicle routing and scheduling problems to the more general integrated operational transportation problems. In this contribution, we analyze the motivation, the chances, the realization, and the challenges of the integrated operational planning and report on experiments for extending the plain Vehicle Routing Problem to a corresponding problem combining vehicle routing and request forwarding by means of different sub-contraction types. The extended problem is formalized as a mixed integer linear programming model and solved by a commercial mathematical programming solver. The computational results show tremendous costs savings even for small problem instances by allowing subcontracting. Additionally, the performed experiments for the operational transportation planning are used for an analysis of the decision on the optimal fleet size for own vehicles and regularly hired vehicles.

• Journal of Radiation Protection and Research
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• v.13 no.2
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• pp.88-94
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• 1988

The radiological impacts due to transportation of irradiated PWR fuel by truck were assessed for incident-free and accident conditions with. the computer code INTERTRAN. The resulting collective doses exposure to different subgroups of the public and of the workers were determined. Resulting collective doses for crewman and the public sharing the transport link and living in a corridor on either side of the route are small. All attempts to quantify the risk from the transport suffer from a lack of good input data. It is in these areas that the most important advances can be made.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 1996.04a
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• pp.749-752
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• 1996

A computer program was developed for the static analusis of a bridge expansion joint mechanism, which is called lazy-tong joint. I t was modelled as a plane truss and statically determinate structure under the assumption of small expansion in bridge girder. The applied load was assumed as a maxium wheel load exerted by a 40th tandem axied tractor-semitrailer truck. By using the developed computer program, reaction forces, axial and bending stresses, deflections, and critical buckling load, etc. of each structural member were analyzed. And they showed good agreement with those analyzed by the comercial F.E.M S/W, ANSYS.

• THE INTERNATIONAL COMMERCE & LAW REVIEW
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• v.40
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• pp.147-167
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• 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.

• Journal of Korean Society of Transportation
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• v.11 no.3
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• pp.67-82
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• 1993

The effects of passing lanes on traffic flow on rural two-lane highways have been investigated in this research. Field study results were compared with the computer simulation model, TRARR, TRARR model appears to be in good agreement with field study results except that average speed and distribution of platoon sizes showed a small amount of discrepancy, which is believed to be caused by too large a headway definition of 6 second for a vehicle platoon. Using the TRARR model, 4 situations including the existing condition, installation of passing lanes, improvement of design speed, and expansion to a four lane highway were evaluated. Traffic volume levels of 500,1000, and 1500 vph and truck composition of 20 and 40% were also considered making a total of 24 computer runs. It is concluded in this research that the installation of passing lanes is the most effective method to improve traffic operation on two-lane high ways except the alternative of four lane highway expansion.

• Transactions of the Korean Society of Automotive Engineers
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• v.4 no.1
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• pp.1-15
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• 1996

This study is concerned with the property changes(chemical and mechanical) of the used oil in diesel engine, which were sampled from a test engine with dynamometer and various cars. The properties of oil are TAN, viscosity, oxidation, ZDTP depletion factor and etc. Also the relation between the change of chemical and antiwear property of used oil was strongly related to ZDTP depletion factor as wall as the change of TAN(total acid number), sulfation and pentan unsoluble contents which were reated to the formation of protect film in sliding area. The oil used in pick-up(small) truck engine was deteriorated within the shortest distance than that of other cars. The antiwear property of used oil was decreased sharply as the running distance were over 5,000km. The oil used to mini bus was the least to deteriorate of properities for the funning distance.