• Transactions of the Korean Society of Automotive Engineers
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• v.25 no.3
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• pp.344-349
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• 2017

Suspension noise from under a passenger car is one of the important factors that impact the perceptual quality for drivers. However, it is difficult to validate this by component level testing in the early stage of development, because suspension noise caused by interaction of the related parts has been found at saleable vehicles late during development or at the manufacturing stage, when many customers have already filed for claims. This study proposed a validation testing under research by the DFSS process that enables reproduction of vehicle level noise by component level testing using a shock absorber with the related parts, such as urethane bumper and top mount. This study also developed a compromised test matrix while analyzing the noise factors through experimental design and analysis of variance to determine what factors can affect noise. Based on this study, we expect that the vehicle level and customer claim can be validated during initial development timing by a more reliable component noise validation test.

• Journal of Korean Society of Steel Construction
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• v.12 no.1 s.44
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• pp.103-110
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• 2000

The suspension bridge is divided by an earth anchor and a self-anchor type according to the anchorage type. This study is to evaluate the dynamic effect of moving vehicles to suspension bridges. The results were presented with the dynamic magnification factor (DMF) by the effect of vehicle speed and weight according to the anchorage type. The vehicle model has 6 degrees of freedom to idealize nonlinear multi-leaf suspensions and elastic tires of tractor-trailer. The bridge was modelled with the 3-dimensional frame element and 3-dimensional elastic catenary cable element. The condition of deck surface is considered using the actual road spectra.

• Journal of the Korean Solar Energy Society
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• v.29 no.6
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• pp.14-21
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• 2009

The demand and installation for photovoltaic system(namely, PV) has grown steadily in Korea. However, the PV system has a various economic viability according to the PV system characteristic variables such as inverter efficiency, miscellaneous power conditioning losses, azimuth and slope of PV array, PV tracking mode, and so on. The other variables are the monthly consumed electric energy and economic related factor such as initial cost, government subsidy, maintenance cost, inflation rate, energy cost escalation rate, discount rate, etc. Therefore, this study is to present economic evaluation of PV system with those concerned factors by calculating internal rate of return, year-to-positive cash flow and net present value indices.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.28 no.3
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• pp.267-273
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• 2004

The purpose of this paper is to develop a systematic design method for the suspension system hard points and compliance elements, which have great influence on the handling stability of a vehicle. In this paper, a method to optimize J-turn responses is presented based on the principles of design of experiments, multi-body dynamic analysis and optimum design technique. The design variables associated with the J-turn maneuver are selected through the experimental design sensitivity analysis using the perturbation method. An objective function is defined as an approximate function for the J-turn characteristics using the TSA(Taylor series approximation). The values of the design variables, which make the optimized J-turn characteristics, are obtained using the conjugate gradient method. The result of the J-turn simulation shows that the optimized vehicle has more improved handling stability than the optimized vehicle.

• Journal of the Korean Society for Precision Engineering
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• v.19 no.1
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• pp.71-78
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• 2002

This paper is concerned with the design and implementation of magnetic damper system to reduce the vibration of suspension system actively. Cylindrical type electro-magnetic actuator with permanent magnet is analyzed and effective controller design is made. Magnetic force analyzed and transfer function for the total system is determined by experimental data using error minimization method. For experiments, simple suspension structure system is utilized, in which a magnetic damper composed of permanent magnet and digital controller is attached. In order to drive the system, bipolar power amplifier of voltage control type is utilized. Stable and high speed control board is used to perform digital control logic for the given system. This paper shows that the magnetic damper system using phase-lead controller excellently reduces vibration of 1-D.O.F (degree of freedom) suspension system.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.12 no.10
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• pp.950-961
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• 2000

The objective of this study is to develop optimal alternative selection model for renewing building equipments system. Cost Breakdown Structure of LCC in HVAC systems are deduced from resonable data and factors. As for Cost Breakdown Structure of LCC in HVAC system, pertinent level, title, CBS number, and block number are determined efficiently. Especially, in addition to current cost factor, it is possible to make Cost Breakdown Structure using present worth method more clear. A model of POWER LCC ver 1.0 used to analyze primary cooling system, heating system, and air conditioning system are POWER LCC ver 1.0_/sub SYSTEM/ : C1+ C2- C3+ C4+ C5+ C6+ C7±C8+ C9- C10/sub -1/+ C10/sub -2/+ C10/sub -3/, and is implemented with consideration of Cost Breakdown Structure and their summation using present-worth method. It is programmed with one of scientific languages, MATLAB 5.3.

• Journal of the Korean Solar Energy Society
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• v.22 no.4
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• pp.97-106
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• 2002

The purpose of this study is to analyze the life cycle cost of primary cooling system by systematic support cost. Life Cycle Cost(LCC) is the process of making an economic assessment of an item, area, system, or facility by considering all significant costs of ownership over an economic life, expressed in terms of equivalent costs. The essence of life cycle costing is the analysis of equivalent costs of various alternative proposals. In order to select economical primary cooling system in early heat source plan stages, the research investigates cost items and cost characteristics during project process phases such as planning/design, construction, maintenance /management, and demolition/sell phases. The study also analyze the life cycle cost by capacity leading to suggest the most economical primary cooling system by systematic support cost.

• Transactions of the Korean Society of Automotive Engineers
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• v.22 no.4
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• pp.72-81
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• 2014

In this study, we perform the optimization of trailing arm bush in a vehicle rear suspension to improve the ride and handling performance. A design problem was formulated considering 2 objective functions and 7 constraints related to vehicle ride and handling performance. PIAnO, one of the PIDO (Process Integration and Design Optimization) tool, was used to automate analysis procedures and perform a design optimization. In order to assess relation between performances and design variables, we perform the DOE (Design of Experiments). To find the optimal solution, we used Progressive quadratic response surface method (PQRSM), one of the design optimization techniques equipped in PIAnO. As an optimization result, we got an optimal solution and could improve lateral force steer off-center by 43.0% while decreasing brake compliance at wheel center by 8.1%.

• Journal of the Korean Society for Railway
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• v.5 no.1
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• pp.40-47
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• 2002

In this study, and analytical method for ride sensitivity analysis of a train with non-linear suspension elements are proposed. Non-linear characteristics of springs and dampers for primary and secondary suspensions of a train are parameterized using polynomial interpolation. Vertical dynamic model of a three-body train running on straight rail with the predetermined roughness expressed in terms of spectral density function is set up and its equations of motion for ride analysis are derived. Using the direct differentiation method, sensitivity equations of the vertical dynamic model with respect to design parameters associated with non-linearity of suspensions are obtained. Based on the sensitivity analysis, improvement of ride is achieved by varying appropriate suspension parameters.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2000.11a
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• pp.620-623
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• 2000

The leaf spring is generally used effectively in load supporting because it has tension-diffused function in comparison with other springs. Nowadays the leaf spring is used widely in the suspensions of automobile and trains. The stiffness and the damping characteristics of the leaf spring being essential for the performance of vehicles, the exact evaluation is required. Various approximate formula are normally used for the leaf spring design. however, accuracy and trust are decreased because the contact and frictional characteristics between leaf plates are generally neglected. In this paper, nonlinear stiffness matrix of the leaf spring is solved by contact-element applying FEM for considering the contact and frictional characteristics between leaf plates. The results of proposed FE model are compared with test data.