• International Journal of Highway Engineering
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• v.12 no.3
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• pp.17-26
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• 2010

Maintenance of the roads and bridges is a major issue for all road administrators around the world, and various initiatives are being implemented in each region for the purpose of controlling the ever increasing road maintenance cost while ensuring the safety of the vehicles driving. Efforts for such initiatives have also been made in Asia and initiatives for managing heavy-weight vehicles have recently gained momentum in Korea and Japan. We have developed a technology for unevenly installing bar-shaped sensors (piezo quartz sensors) to enable dynamic axle load measurement at a highly accurate level, and have estimated our measurement accuracy of axle load/gross weight, etc. on an actual road. The measurement accuracy of the axle load/gross weight varies significantly depending on the number of sensors installed. In our implementation, the target accuracy was set to below ${\pm}5%$ for gross weight measurement so that automatic regulation can be applied. We have achieved our target by installing 8-point measurement system. However, to have this technology widely accepted, it was necessary to reduce the system size so that it can be easily implemented. Therefore, we have estimated the relationship between the measurement accuracy and the system size (number of measurement points), and have come up with the proposal of 3-point measurement as an optimum number of measurement points, and have estimated its performance on an actual road. Additionally, we evaluated the relationship between the measurement accuracy and vehicle velocity.

• Journal of Korean Society of Transportation
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• v.19 no.3
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• pp.45-58
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• 2001

Subjective mental workload assessment technique becomes a standard human factors and human-machine interface evaluation tool for the evaluation of ITS(Intelligent Transport Systems)-oriented information systems as well as the drivers visual activity analysis, physiological indices(GSR, EEG, ECG, etc.), secondary task performance, reaction time. vehicle control parameters(speed, steering behavior, accelerator control) that are widely applied for transportation and vehicle systems to evaluate the safety, to decide the system or design alternatives, and to establish the design guidelines. This paper reviewed and compared the most globally employed four mental workload assessment techniques that have been designed for the use of various human-machine systems and ITS-oriented in-vehicle information systems. NASA-TLX(National Aeronautics and Space Administration-Task Load Index). SWAT(Subjective Workload Assessment Technique), MCH(Modified Cooper-Harper) scale, and recently developed RNASA-TLX(Revision of NASA-TH) were compared in terms of sensitivity and subjective evaluations to derive the human-machine interface evaluation guidelines for the application of ITS-oriented in-vehicle information systems. Then, experiment results supported that RNASA-TLX is the prospective tool for the mental workload assessment of ITS-oriented in-vehicle information systems.

• The Korean Journal of Pharmacology
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• v.12 no.1
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• pp.63-67
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• 1976

The purpose of the present study was to see the Panax Ginseng has any influence upon the acquisition of the conditioned avoidance response(CAR) in rats. Sixty male rats of Holtsman strain were used. The animal weighed between 20 and 300 gm at the beginning of the experiment. Training of avoidance conditioning was done in a two-way shuttle box which was separated into two compartments by a guilotine door. The conditioned stimulus (CS) was a light beam and the unconditioned stimulus (UCS) was an electric shock. The shock was presented 10 sec. after onset of the CS and continued until the subject crossed to the opposite safety compartment within 20 sec. after onset of UCS. Each S was received 30 trials a day (one session) for 6 consecutive sessions. The number of CR which avoided successfully without having shock and the number of fecal balls during the conditioning were served as an index of learning performance and emotionality. The results obtained as follows. All doses of Ginseng saponin treated animals showed more CR than control, but did not differ significantly from control. Ginseng saponin treated animals with the doses of $50{\sim}100\;mg/kg$ defecated the fecal balls significantly less frequent than the placebo control during CAR.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.11 no.10
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• pp.3911-3916
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• 2010

In this paper we describe contents and results on running test for ATP on-board equipment, which has propelled as one of the research projects, so called, "Reliability assessment and operation technology development for Korean-type tilting trains" in order to ensure the safety and operation efficiency of tilting trains. We developed tilting trains for the speed-up of conventional lines and for the passenger service improvement where the KTX is not available. And we made progress the operation trial test in the 120,000 km distance with the use of ATS equipment, used in existing lines, for the purpose of the reliability assessment of the developed tilting trains. We decided to accelerate the speed for more than 200km/h with respect to the 6 existing lines including Jungang-line and Chungbuk-line where KTX has not operated. According to this decision, Train control system is to be changed from ATS to ATP. We should have installed an ATP on-board unit in tilting trains and verified the operational suitability, therefore we installed the same ATP on-board unit on tilting trains as that used in the ATP construction project on Gyeongbu-line and Honam-line, and verified that the function and performance of the installed ATP on-board unit conformed to the tilting trains operation.

• Proceedings of the Korean Institute Of Construction Engineering and Management
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• autumn
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• pp.355-358
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• 2002

Since the 1960s, though there were brisk supply in apartment housing, there were no preparation in standard for to extend the life(durability) of apartment housing by maintaining the $social{\cdot}physical$ aspect of apartment housing, and in standard maintenance system. So problem such as facilities safety and residence environment has occurred. Like the condition written above, efficient usage of housing resource by the maintenance of apartment housings in a state of great urgency. In service aspect of apartment housing, establishment of accurate long term repair plan and estimate of repair appropriation fund can prevent housing's fast-deterioration. But to the performers of the maintenance, like house managers and the tenants at the subject building has little awareness of necessity in establishment of accurate long term repair plan and accumulation of repair appropriation fund. Unestablishment of long term repair plan arises problem such as approval of repair appropriation fund's unreasonable accumulation. Hence, for the utmost performance of apartment housing and to extend the economic life of a building, the method of establishment of long term repair plan and estimate of repair appropriation fund on reliable basis is to be proposed.

• Proceedings of the Korean Institute Of Construction Engineering and Management
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• autumn
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• pp.73-81
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• 2003

The construction industry has been experiencing a major challenge in its work force, 'the shortage of skilled craft workers.' This problem has been caused by several factors such as the poor image of the construction industry, lack of training and education, unclear career path, declining wages, and changing work force demographics. A 'step-change' approach called the 'Two-Tier Work Force Strategy' has been proposed by the Center for Construction Industry Studies (CCIS) to deal with the work force related issues in a radical way. It is composed of two separate strategies, Tier I and II. The Tier I strategy uses less skilled and task trained craft workers, and has a larger administrative site management team than the Tier II strategy. The Tier II strategy utilizes fewer, better-educated, and higher skilled workers who perform some lower-management functions in addition to craft functions. They are paid more, but produce more through higher skills, stay on the job longer through multi-skilling, and deliver improved project performance in safety, quality, schedule, and cost The Two-Tier Work Force Strategy has the potential to resolve the current work force problems and foster a better work force environment in the future.

• Resources Recycling
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• v.21 no.5
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• pp.79-87
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• 2012

With the increasing size and universalization of lithium-ion batteries, the development of cathode materials has emerged as a critical issue. The energy density of 18650 cylindrical batteries had more than doubled from 230 Wh/l in 1991 to 500 Wh/l in 2005. The energy capacity of most products ranges from 450 to 500Wh/l or from 150 to 190 Wh/kg. Product developments are focusing on high capacity, safety, saved production cost, and long life. As Co is expensive among the cathode active materials $LiCoO_2$, to increase energy capacity while decreasing the use of Co, composites such as $LiMn_2O_4$, $LiCo_{1/3}N_{i1/3}Mn_{1/3}O_2$, $LiNi_{0.8}Co_{0.15}Al_{0.05}O_2$, and $LiFePO_4$-C (167 mA/g) are being developed. Furthermore, many studies are being conducted to improve the performance of battery materials to meet the requirement of large capacity output density such as 500Wh/kg for electric bicycles, 1,500Wh/kg for electric tools, and 4,000~5,000Wh/kg for EV and PHEV. As new cathodes active materials with high energy capacity such as graphene-sulfur composite cathode materials with 600 Ah/kg and the molecular cluster for secondary battery with 320 Ah/kg are being developed these days, their commercializations are highly anticipated.

• Tunnel and Underground Space
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• v.12 no.1
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• pp.52-69
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• 2002

The WIPP (Waste Isolation Pilot Plant), located 42km east of Carlsbad, New Mexico (NM), in bedded salt 655m below the surface, is a mined repository constructed by the US DOE for the permanent disposal of transuranic (TRU) wastes generated by activities related to defence of the US since 1970. Its historical disposal operation began in March 1999 following receipt of a final permit from the State of NM after a positive certification decision for the WIPP was issued by the EPA in 1998, as the first licensed facility in the US for the deep geologic disposal of radioactive wastes. The CCA (Compliance Certification Application) for the WIPP that the DOE submitted to the EPA in 1966 was supported by an extensive performance assessment (PA) carried out by Sandia National Laboratories (SNL), with so-called 1996 PA. Even though such PA methodologies could be greatly different from the way we consider for HLW disposal in Korea largely due to quite different geologic formations in which repository are likely to be located, a review on lots of works done through the WIPP PA studies could be the most important lessons that we can learn from in view of current situation in Korea where an initial phase of conceptual studies on HLW disposal has been just started. The objective of this art report is an overview of the methodology used in the recent WIPP PA to support the US DOE WIPP CCA and some relevant results completed by SNL.

• Progress in Medical Physics
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• v.23 no.3
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• pp.162-168
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• 2012

In proton therapy, in vivo dose verification is one of the most important parts to fully utilize characteristics of proton dose distribution concentrating high dose with steep gradient and guarantee the patient safety. Currently, in order to image the proton dose distribution, a prompt gamma distribution detection system, which consists of an array of multiple CsI(Tl) scintillation detectors in the vertical direction, a collimator, and a multi-channel DAQ system is under development. In the present study, the optimal design of prompt gamma distribution detection system was studied by Monte Carlo simulations using the MCNPX code. For effective measurement of high-energy prompt gammas with enough imaging resolution, the dimensions of the CsI(Tl) scintillator was determined to be $6{\times}6{\times}50mm^3$. In order to maximize the detection efficiency for prompt gammas while minimizing the contribution of background gammas generated by neutron captures, the hole size and the length of the collimator were optimized as $6{\times}6mm^2$ and 150 mm, respectively. Finally, the performance of the detection system optimized in the present study was predicted by Monte Carlo simulations for a 150 MeV proton beam. Our result shows that the detection system in the optimal dimensions can effectively measure the 2D prompt gamma distribution and determine the beam range within 1 mm errors for 150 MeV proton beam.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.34 no.11
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• pp.1027-1033
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• 2010

A two-phase (gas-liquid) flow is a common phenomenon in fluidic systems, e.g., fluidic systems in the electro-magnetic or nuclear power generation industry and in the steel industry. The measurement of a two-phase flow is important for guaranteeing the safety of the system and for achieving the desired performance. The measurement of the void fraction, which is one of the parameters of the two-phase flow that determines the pressure drop and heat transfer coefficient, is very important. The time resolution achieved by employing the impedance method that can be used to calculate the void fraction from the impedance of the fluid is high because the electric characteristics are taken into account. Therefore, this method can be employed to accurately measure the void fraction without distortion of flow in real time by placing electrodes on the walls of the tubes. Coney analytically studied a ring-type impedance meter, which can be employed in a circular tube. The aim of this study is to experimentally verify the robustness of a three-ring impedance meter to variations in the electric conductivity of the fluid; this robustness was suggested by Coney but was not experimentally verified.