• Proceedings of the KSR Conference
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• 2011.10a
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• pp.1185-1190
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• 2011

In designing cut and cover tunnels, load combination applied Korea seismic design code of urban transit and its sections applied Korea concrete code 2003. However, by revision of Korea concrete code in 2007, engineers have been experiencing difficulties in their work. In this study, application of Korea concrete code 2007 for designing is reviewed by comparing load combination of related codes and member force.

• Smart Structures and Systems
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• v.20 no.4
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• pp.451-460
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• 2017

This work produces a new model of nonlocal thermoelastic nanobeams of temperature-dependent physical properties. A nanobeam is excited by harmonically varying heat and subjected to an exponential decaying time varying load. The analytical solution is obtained by means of Laplace transform method in time domain. Inversions of transformed solutions have been preceded by using calculus of residues. Effects of nonlocal parameter, variability thermal conductivity, varying load and angular frequency of thermal vibration on studied fields of nanobeam are investigated and discussed.

• Proceedings of the KIEE Conference
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• 1999.11b
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• pp.134-136
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• 1999

Not much work has been carried out on the load flow analysis of distribution networks. This paper introduces Newton-Raphson method using Distflow equation and Forward Sweeping method in the distribution networks. And that efficient solution scheme in a radial distribution network is presented. Also, simulation results of both Newton-Raphson method and Forward Sweeping method applied to a 22.9kV distribution system model with 120 load buses are analized and evaluated.

• Proceedings of the IEEK Conference
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• 2006.06a
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• pp.209-210
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• 2006

Hierachical Mobile IPv6 (HMIPv6) solves Micro-mobility protocol problem about Handover. Mobility Anchor Point(MAP) helps reducing the handover, but this makes a load on the MAP. Besides the MAP operates this work everytime, and every Nodes. In this paper, we propose the algorithm that reduces the amount of Map working.

• Proceedings of the KIEE Conference
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• 2003.11a
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• pp.463-465
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• 2003

This paper adopts the methods of dynamic programming based on priority and the objective function is to maximize the amount of priority. The Purpose of this work is to schedule the direct load control with approciate constrints. To demonstrate the effectiveness of the study, sample data is used about 54 load. And the results of sample are described in this.

• Journal of the Ergonomics Society of Korea
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• v.25 no.3
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• pp.61-66
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• 2006

Awkward work postures in workshop highly affect on work-related musculoskeletal disorders(WMSDs). Especially, in automobiles assembly process, these awkward work postures of workers may cause serious injury and illness. This study is to compare the performance among the evaluation tools which can measure the work-loads caused by the awkward work postures in automobiles assemble process. RULA, REBA and TVAL(Toyota Verification of Assembly Line) are used as the evaluation tools. The 85 jobs selected in the automobiles assembly process are applied to the three tools and their performances are analyzed after the evaluation of the work-load in each job. Through various measures of performance such as statistical test, DUNCAN test, regression test etc., the tendencies and characteristics among them are analyzed in detail.

• Safety and Health at Work
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• v.4 no.1
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• pp.46-51
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• 2013

Objectives: Load carrying tasks are recognized as one of the primary occupational factors leading to slip and fall injuries. Nevertheless, the mechanisms associated with load carrying and walking stability remain illusive. The objective of the current study was to apply local dynamic stability measure in walking while carrying a load, and to investigate the possible adaptive gait stability changes. Methods: Current study involved 25 young adults in a biomechanics research laboratory. One tri-axial accelerometer was used to measure three-dimensional low back acceleration during continuous treadmill walking. Local dynamic stability was quantified by the maximum Lyapunov exponent (maxLE) from a nonlinear dynamics approach. Results: Long term maxLE was found to be significant higher under load condition than no-load condition in all three reference axes, indicating the declined local dynamic stability associated with load carrying. Conclusion: Current study confirmed the sensitivity of local dynamic stability measure in load carrying situation. It was concluded that load carrying tasks were associated with declined local dynamic stability, which may result in increased risk of fall accident. This finding has implications in preventing fall accidents associated with occupational load carrying.

• Transactions of the Korean Society of Automotive Engineers
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• v.20 no.5
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• pp.88-94
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• 2012

Development trend of modern HSDI diesel engine is now focusing on low fuel consumption and emission because of strong interest in global environmental protection. Two big branches of criteria for modern diesel engine development are down sizing and down speeding. Down sizing keeps engine operation condition to the direction of higher load and thus pursuing for better thermal efficiency. But this may cause degraded vehicle dynamic performance because of reduced back up torque. Down speeding keeps engine operation condition to the direction of slightly higher load and lower engine speed. Therefore reduction of back up torque can be limited within flat torque area. This study analyzed fuel economy effect of down speeding on a vehicle powered by HSDI diesel engine in aspect of engine friction work, intake and exhaust pumping work, exhaust hat loss and thermal loss of fuel leakage of fuel injection system. Contribution factor of each engine and vehicle related parameters under basic and down speeding condition were compared and work balance of down speeding during NEDC was analyzed.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.32 no.5
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• pp.411-418
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• 2008

In this work, the effect of strength mismatch on plastic limit loads is quantified for similar metal weld plates with cracks under tension load, via three-dimensional, small strain elastic-perfectly plastic finite element analyses. Relevant variables related to plate geometry and crack length are systematically varied, in addition to the weld width. An important finding is that mis-match limit loads can be uniquely quantified through strength mis-match ratio and one geometry-related parameter. Based on the proposed limit load solutions, reference stress based J-integral estimates is also investigated. When the reference stress is defined by the mis-match limit load, predicted J-integral values agree overall well with FE results.

• Proceedings of the KIEE Conference
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• 2002.07d
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• pp.2076-2078
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• 2002

This paper presents an Intelligent Balance Beam Controller(IBBC) which can estimate the inertia of load automatically. Balance Beam controller is a kind of construction tool which can control the attitude of the load hanging in the air such as a beam carried by crane. In our previous work, Balance Beam had been built to control the object in air using a mechanical gyro system having a position controllable gimbal structure. In field application the load inertia for operation is not easy to figure out because the weight and shape which determines the inertia, varies depending on the object to be carried. Therefore it is difficult for a worker to operate a Balance Beam and an accident could be caused occasionally. We designed an automatic load estimator to measure the inertia of arbitrary load by using an angular velocity sensor that is installed on the Balance Beam. Simulation results and current status for implementation are presented.