• Korean Journal of Air-Conditioning and Refrigeration Engineering
• /
• v.19 no.1
• /
• pp.68-76
• /
• 2007

As an alternative approach to evaluate the unit heating load for apartment houses, we newly developed and proposed unit building method. The new method, which calculates the heating load of an apartment building as a whole, conceptually corresponds to integral analysis of building heat loss, while the existing unit apartment method to differential analysis. Four typical building models of Korean-style apartment house and two dynamic load calculation programs were selected to validate the present method under realistically imposed conditions. Eight sets of unit heating load calculated respectively by unit building and unit apartment methods showed excellent agreements regardless of building model and simulation program. It is expected that the unit building method can take the place of the unit apartment method due to fewer modeling assumptions as well as less computational efforts. Additional calculations to investigate the effects of various parameters on unit heating load yield good consistencies with known facts, and re-confirm the validity.

• Proceedings of the Korean Society for Technology of Plasticity Conference
• /
• 2001.05a
• /
• pp.201-204
• /
• 2001

The tension levelling process is performed to elongate the strip plastically in combination of tensile and bending strain so that all longitudinal fibers in the strip have an approximately equal amount of length and undesirable strip shapes are corrected to the flat shape. This paper is concerned with a simulation of the tension levelling process based on the analysis of the unit model for the tension leveller. Analysis technique such as the sequential analysis of the nit model is suggested and verified with the assembly analysis of the unit model for the effective and economic analysis of the full set of the tension leveller. Analysis of the full tension levelling process using sequential unit models is carried out and provides the effect of the intermesh and optimum amount of the intermesh in tension levelling process.

• Journal of the Korean housing association
• /
• v.16 no.1
• /
• pp.55-63
• /
• 2005

The purpose of this study is to find a way of solving on parking problems at apartment complex through the trend analysis research of the parking demands according to the housing unit size. The subjects of this study are high-rise apartment complexes in Daegu city which are constructed within 10 years. The parking demand according to the housing unit size at apartment complexes had been surveyed every July for 4 years from 2000 to 2003. Specially, we knew that the parking demand of $85 m^2$ below sized housing unit at apartment complex was exceeded architectural regulation of parking supply, and the parking demand of $85 m^2$ over sized housing unit at apartment complex was kept within architectural regulation of parking supply. And, the estimating formula that can predict the future parking demand by the trend analysis according to the housing unit size at apartment complexes in Daegu city was gotten through this study. But, in order to get more accurate estimating formula, it should be based on data of funker research and investigation about apartment complexes and it should be studied continuously.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
• /
• v.32 no.4
• /
• pp.391-396
• /
• 2006

The CT number is called Hounsfield unit(HU). Generally HU has a score between +1000 from -1000, and it is standardized usingthe air(-1000), water(0), and compact bone(+1000). Hounsfield Unit to standardize the density in computed tomography using the air and water has been used to analysis of lesion in other medical field. Computed tomography is popular method to analysis of lesion in oral & maxillofacial field but the analysis about density of lesion by Hounsfield unit is still obscure. For this study, computed tomography taken in Dankook University Dental Hospital and Hounsfield unit was measured to compare the difference of jaw bone lesion as cystic lesion, benign tumor, malignant tumor.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
• /
• 2012.10a
• /
• pp.169-174
• /
• 2012

Reduction unit is one of the most important components for railway vehicle because torque of motor must be transmitted to wheels of vehicle by reduction unit. However, According to advanced studies, it has been often broke down due to the damage, fatigue and wear of gear. To solve this problem, defect diagnosis methods of gear have been mainly using the vibration diagnosis technology through vibration waveform and frequency analysis. However, We should know vibration characteristics of normal state reduction unit prior to defect diagnosis. So in this paper, We had analyzed vibration characteristics of reduction unit in order to utilize monitoring system development. Comparison of targets is the vibration characteristics of normal state reduction unit about Electric Multiple Unit(EMU) and the High-speed trains(KTX, KTX II).

• Journal of Applied Reliability
• /
• v.6 no.2
• /
• pp.151-161
• /
• 2006

This article is concerned with cost analysis model in periodic maintenance policy. The repair policy is differently applied according as unit importance during an item being used and unit restoration during an item being failed. So in this paper the repair policy with minimal repair is considered as follow : as the occurrence of failure between minimal repair and periodic interval time, unit is replaced by a spare unit until the periodic maintenance time arrived. Then total expected cost per unit time is calculated according to scale parameter of failure distribution in a view of customer's. The total expected costs are included repair and usage cost : operating, fixed, minimal repair, periodic maintenance and spare unit cost. Numerical example is shown in which failure time of item has Erlang distribution.

• Nuclear Engineering and Technology
• /
• v.52 no.10
• /
• pp.2221-2229
• /
• 2020

After the Fukushima Daiichi nuclear power plant (NPP) accident, level 3 probabilistic safety assessment (PSA) has emerged as an important task in order to assess the risk level of the multi-unit NPPs in a single nuclear site. Accurate calculation of the radionuclide concentrations and exposure doses to the public is required if a nuclear site has multi-unit NPPs and large number of people live near NPPs. So, there has been a great need to develop a new method or procedure for the fast and accurate offsite consequence calculation for the multi-unit NPP accident analysis. Since the multi-unit level 3 PSA is being currently performed assuming that all the NPPs are located at the same position such as a center of mass (COM) or base NPP position, radionuclide concentrations or exposure doses near NPPs can be drastically distorted depending on the locations, multi-unit NPP alignment, and the wind direction. In order to overcome this disadvantage of the COM method, the idea of a new multiple location (ML) method was proposed and implemented into a new tool MURCC (multi-unit radiological consequence calculator). Furthermore, the MURCC code was further improved for the multi-unit level 3 PSA that has the arbitrary number of multi-unit NPPs. The objectives of this study are to (1) qualitatively and quantitatively compare COM and ML methods, and (2) demonstrate the strength and efficiency of the ML method. The strength of the ML method was demonstrated by the applications to the multi-unit long-term station blackout (LTSBO) accidents at the four-unit Vogtle NPPs. Thus, it is strongly recommended that this ML method be employed for the offsite consequence analysis of the multi-unit NPP accidents.

• Journal of The Korean Society of Agricultural Engineers
• /
• v.65 no.3
• /
• pp.15-28
• /
• 2023

The compaction properties of the soil change depending on the physical properties, and are also affected by crushing of the particles. Since the particle size distribution of soil affects the engineering properties of the soil, it is necessary to analyze the material properties to understand the compaction characteristics. In this study, the size of each sieve was classified into four in the particle size analysis as a material property, and the compaction characteristics were evaluated by multiple regression and maximum dry unit weight. As a result of maximum dry unit weight prediction, multiple regression analysis showed R² of 0.70 or more, and DNN analysis showed R² of 0.80 or more. The reliability of the prediction result analyzed by DNN was evaluated higher than that of multiple regression, and the analysis result of DNN-T showed improved prediction results by 1.87% than DNN. The prediction of maximum dry unit weight using particle size distribution seems to be applied to evaluate the compacting state by identifying the material characteristics of roads and embankments. In addition, the particle size distribution can be used as a parameter for predicting maximum dry unit weight, and it is expected to be of great help in terms of time and cost of applying it to the compaction state evaluation.

• Korean Institute of Interior Design Journal
• /
• v.15 no.3 s.56
• /
• pp.102-110
• /
• 2006

The purpose of this study was to find out the spacial characteristics from the $69.42-11.70m^2$ unit plans of the apartment houses in Jeon-ju city, and to check up on the general spacial principles of Korean apartment unit plans. The content analysis method and the survey method were used for this study. The data of apartment unit plans and the questionnaires were collected from apartment offices or real estate agency offices. The data of 157 unit plans and 190 questionnaires were analyzed. The results of this study were as follows; 1) The general spacial principles of Korean apartment unit plans, the tendency of front 3-bay unit plan, the openness of living room, the Anbang with a bathroom and a dressroom, the utility room as a kitchen support space, and the addition of balconies, were showed in those of Jeon-ju city. 2) There was a new tendency, the front room arrangement of Anbang-living room-bedroom was changed into Anbang-living room-bathroom or kitchen, in them. 3) The characteristics of L-DK floor plans that the closeness of DK from exterior space and the interior openness and exterior privacy of L were showed in them. 4) The entrance was needed a intermediate space as a balcony or a former space, in them. These tendencies on unit plans of the apartment houses in Jeon-ju city were followed the general spacial principles of Korean apartment unit plans.

• The Transactions of The Korean Institute of Electrical Engineers
• /
• v.64 no.3
• /
• pp.485-491
• /
• 2015

This paper shows the design improvement and test model of FAU (Frequency Analysis Unit) in PDD (Partial Discharge Diagnosis system) for 800kV GIS (Gas Insulated Switchgear). We found some problems during operation of previous FAU, such as the aging of fiber-optic converter that can cause communication error, the malfunction of signal analysis circuit etc. And then we solved those problems by design improvement and verified the performance through type test. To monitor partial discharge, the performance of UHF sensor is important but the performance of frequency analysis unit is also very important. So we solved communication error, the malfunction of signal analysis circuit and then increased the operation reliability of FAU by improving fiber-optic converter and signal analysis circuit. Accredited testing laboratory carried out the performance verification test according to performance test criteria and procedure of reliability test standards, IEC-60225, 61000 and 60068 etc. We confirmed the test results which correspond with the performance test criteria.