• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2006.05a
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• pp.7-10
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• 2006

A quasi-equilibrium model is used in order to aid movement and ballistic analysis for a propellant actuated device(PAD) system. The validity of the model is examined by experiments of a PAD system. The appropriateness of its usage for application was explored by comparing the tendency of experiments and analysis results, and the coefficients of friction and heat loss were obtained. The design method developed will be applied to the design of PAD systems.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2009.05b
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• pp.149-153
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• 2009

Today, the form of competition among companies quickly changes in new paradigm. In the past company activity was performed independently, but now dependently. With global age, that change is essential, the introduction of a system that integrates a series of courses is needed for the success of members. Nevertheless, those change are very slow in construction industry, that causes a lot of loss in project process. Construction industry produce structures with collaboration of other industries. There are difficulties that only one company make it, alone. In this trend, cooperation is essential. but the process of original brings a lot of loss From this perspective, this study will prove dependencies of construction industry. Draw out each factor from industrial cooperation, those analyze correlation with system dynamics. In conclusion, this study performs a basic research about 'Integrated Management System' of construction project.

• Food Science and Preservation
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• v.1 no.1
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• pp.37-43
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• 1994

A microcomputer system consisting of 16-bit microcomputer, PCL-711S interface board, censors, and converters have been set up in order to automatically measure temperature, humidity and weight loss which are major variables of storage of apple. This system was operated by PC-LabDAS software. It has been possible to measure continuously the weight loss of Fuji apple stored in CA with the weight converter made by a miniature load cell and a strain amplifier. The temperature was checked by a k-type thermocouple and Pt 100 $\Omega$ RTD, and humidity by PQ653JAl humidity sensor. It has been possible to set up a linear equation which showers high correlationship between the estimate of temperature, weight humidity and the output of the converter in that r2 is more than 0.99. Transpiration rate, a significant factor of quality deterioration for CA storage of apple, can be estimated with these values.

• Journal of international Conference on Electrical Machines and Systems
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• v.1 no.4
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• pp.412-418
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• 2012

Eddy current brakes are electromechanical devices used as variable mechanical loads for testing electrical machines. Accurate modeling of eddy current loss is an important t factor for optimum design of eddy brake systems. In this second part, we propose novel formulations of eddy current loss in novel claw-pole eddy brake system. The proposed model for eddy current loss in novel claw-pole eddy brake system depends on the size of the claw poles. Also, in this paper, the flux density is measured by using the magnetic circuit of the novel claw pole. The model results are compared with experimental results and they are found to be in good agreement.

• Journal of the Korean Solar Energy Society
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• v.31 no.3
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• pp.17-22
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• 2011

Techniques for mismatch loss minimization to increase the PV system efficiency are under development recently. In this paper, a method to make diagnosis of PV module mismatch is presented, which uses a concept of operating point factor. The method is based on the fact that the ratio of the incremental conductance of a PV module to instantaneous conductance is 1 when the module is operating at its maximum power point. The variations of module voltage and current are taking place by the maximum power point tracker in the power conditioning units of PV system. The effectiveness of the method is verified through an application to a real PV system.

• Journal of Wetlands Research
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• v.21 no.2
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• pp.163-172
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• 2019

The USLE P factor is a factor that varies depending on how croplands are managed and cultivated. Previous studies tend to overestimate the amount of soil loss because the factor was estimated from the slope of the watershed rather than the estimate of each cultivated land. In addition, the accuracy of estimating the soil loss is decreasing due to the fact that the factor is calculated without considering various conditions of cultivated land defined by Wishmeier and Smith. In order to overcome these problems, the Ministry of Environment (MOE) has proposed to establish the topsoil notification and calculate the P factor according to the cultivation methods (e.g., tillage system, support practice). However, it is required to apply the conditions proposed in the United States to domestic circumstances as it is causing uncertainties. Thus, this study selected the watersheds where soil loss was serious (Haean, Jaun, Banbyeoncheon), measured the actual slopes and slope lengths, and examined the crop, tillage systems, and support practice for each cultivated land. The P factors were recalculated considering the actual conditions of cultivated land and compared to the factors proposed by the previous studies (MOE). As the result of the study, the P factors calculated based on the previous studies were 0.8 ~ 1.0 in three watersheds. On the other hand, it is confirmed that there is a significant difference between the factors notified by MOE and estimated by reflecting the topography and cultivation methods in this study. Therefore, it is considered that the research for developing the cultivation conditions to calculate the P factor suitable for the domestic environment should be continuously carried out.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2002.11b
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• pp.869-874
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• 2002

Hermetic rotary compressor is one of the most important components for air conditioning system since it has a great effect on both the performance and the noise and vibration of the system. Noise and vibration of rotary compressor is occurred due to gas pulsation during compression process and unbalanced dynamic force. In order to reduce noise and vibration, It is necessary to identify sources of noise and vibration and effectively control them. Many approaches have been tried to identify noise sources of compressor. However, compressor noise source identification has proven to be difficult since the characteristics of compressor noise are complicated due to the interaction of the compressor parts and gas pulsation. In this work, Statistical Energy Analysis has been used to trace the energy flow in the compressor and identify transmission paths from the noise source to the sound field.

• Journal of Advanced Navigation Technology
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• v.14 no.2
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• pp.170-175
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• 2010

This article proposed polarization selective antenna for UHF RFID system. The proposed antenna is consist of microstrip patch antenna with dual feeding and two SPDT switches and a SP4T switch and 3dB hybrid coupler. Through control of voltage of switches, the proposed reader antenna can select horizontally linear polarization, vertically linear polarization, left-hand circular polarization (LHCP) and right hand circular polarization (RHCP). The proposed reader antenna satisfied 2:1 VSWR at 902MHz ~ 928MHz. and 3dB under AR(axial ratio). And it can select appropriative polarization with user environment and tag polarization. So it minimize PLF and increased reading distance.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.18 no.6
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• pp.114-120
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• 2004

The paper proposes a method calculate the allocations of real power losses in transmission lines to individual loads based on loss distribution factors and compares them with those using marginal loss factors. The proposed method is implemented by defining loss distribution factors and analysing the individual loads' shares in the transmission line losses. Computer simulations on a 9-bus sample system verify effectiveness of the algorithm proposed and give an assertion that it is desirable to allocate power losses to loads using loss distribution factors rather than based on marginal loss factors.

• Journal of the Korean Society for Nondestructive Testing
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• v.22 no.4
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• pp.369-376
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• 2002

The dielectric properties of cereal grains such as short-grain rough rice, brown rice and barley with various moisture contents were determined by measuring the attenuation and phase shift of the microwave signal trough the grain samples at 9.5GHz. The microwave free-space transmission measurement system consisted of sample holder, horn antenna and network analyzer. Dielectric constant and loss factor of grain samples increased with moisture content and bulk density and agreed well with previous research results. Moisture density, which is defined as the product of moisture content and bulk density, was proposed as a bulk density and variety compensation factor. The technique for measurement of dielectric properties based on free-space transmission may be useful for other particulate materials.