• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2007.11a
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• pp.1333-1334
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• 2007

Page-oriented angle multiplexing Holographic data storage system is the one of promising techniques for high capacity and data transfer rate, but its size and narrow tilt margin is pointed as a demerit. To overcome this weak point, in this paper, 2-axis deck mechanism for compensation of disc is employed to Compact size Holographic Data Storage (CHDS) which consists of minimized optical components and small 2-axis actuator moving linear & angle direction. Compensation of radial/tangential disc tilt with 2-axis deck mechanism is demonstrated.

• Journal of Korean Institute of Industrial Engineers
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• v.9 no.2
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• pp.27-35
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• 1983

This paper describes a procedure of generating economic cutter-location(CL) data for the machining of sculptured surfaces on a multi-axis NC milling machine. Measures of economy are the machining time (cutter move distance) and the length of NC tape (number of CL data points). The presented procedure minimizes both the number of CL data and the total distance of cutter moves, for a given cutter (spherical end-mill) size and parameteric cutting direction, while satisfying given tolerance requirements. The procedure has been implemented in FORTRAN for a smooth composite Bezier surface. The maximum allowable cutter size is calculated by the program so that a user can choose a cutter size. CL data can be generated in both parametric directions u and v. Experimental results show that there are significant differences between the parametric directions, and that cutter size should be as large as possible in order to minimize the cutting time and NC tape length.

• Proceedings of the PSK Conference
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• 2003.04a
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• pp.117.2-118
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• 2003

Sample size calculations plays an important role in a bioequivalence trials and is determined by considering power under the alternative hypothesis. The regulatory guideline recommends that $2{\times}2$ crossover design is conducted and raw data is log-transformed for statistical analysis. In this paper, we discuss the sample size calculation in $2{\times}2$ crossover design with the log-transformed data.

• Korean Journal of Computational Design and Engineering
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• v.16 no.5
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• pp.344-350
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• 2011

In injection molding industries, CAE analyses are generally used to find out problems predicted during the process of manufacturing. The results of CAE analyses consist of much in formation such as meshes and stress, so that the size of data is pretty large. To reduce the size of the data and to make it easy to share, the CAE result to JT translator is proposed in this paper. The translator consists of three modules to translate CAE result to JT format; Extracting module gets ASCII data of product shape and the result values of CAE analysis. Sorting module and mapping module make an element data set and JT file with the data extracted from Extracting module respectively. To the JT files, engineers are able to append product properties and their comments, so that they can share the whole history of the analysis process. In addition, our case study shows that the size of JT format is reduced by almost 90% of its original data format.

• Journal of The Korean Society of Agricultural Engineers
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• v.64 no.3
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• pp.9-24
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• 2022

Currently, a vast amount of hydrologic data is accumulated in real-time through automatic water level measuring instruments in agricultural reservoirs. At the same time, false and missing data points are also increasing. The applicability and reliability of quality control of hydrological data must be secured for efficient agricultural water management through calculation of water supply and disaster management. Considering the characteristics of irregularities in hydrological data caused by irrigation water usage and rainfall pattern, the Korea Rural Community Corporation is currently applying the Hampel filter as a water level data quality management method. This method uses window size as a key parameter, and if window size is large, distortion of data may occur and if window size is small, many outliers are not removed which reduces the reliability of the corrected data. Thus, selection of the optimal window size for individual reservoir is required. To ensure reliability, we compared and analyzed the RMSE (Root Mean Square Error) and NSE (Nash-Sutcliffe model efficiency coefficient) of the corrected data and the daily water level of the RIMS (Rural Infrastructure Management System) data, and the automatic outlier detection standards used by the Ministry of Environment. To select the optimal window size, we used the classification performance evaluation index of the error matrix and the rainfall data of the irrigation period, showing the optimal values at 3 h. The efficient reservoir automatic calibration technique can reduce manpower and time required for manual calibration, and is expected to improve the reliability of water level data and the value of water resources.

• Journal of Information Processing Systems
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• v.2 no.2
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• pp.76-81
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• 2006

A PDA is used mainly for downloading data from a stationary server such as a desktop PC in an infrastructure network based on wireless LAN. Thus, the overall performance depends heavily on the performance of such downloading with PDA. Unfortunately, for a PDA the time taken to receive data from a PC is longer than the time taken to send it by 53%. Thus, we measured and analyzed all possible factors that could cause the receiving time of a PDA to be delayed with a test bed system. There are crucial factors: the TCP window size, file access time of a PDA, and the inter-packet delay that affects the receiving time of a PDA. The window size of a PDA during the downstream is reduced dramatically to 686 bytes from 32,581 bytes. In addition, because flash memory is embedded into a PDA, writing data into the flash memory takes twice as long as reading the data from it. To alleviate these, we propose three distinct remedies: First, in order to keep the window size at a sender constant, both the size of a socket send buffer for a desktop PC and the size of a socket receive buffer for a PDA should be increased. Second, to shorten its internal file access time, the size of an application buffer implemented in an application should be doubled. Finally, the inter-packet delay of a PDA and a desktop PC at the application layer should be adjusted asymmetrically to lower the traffic bottleneck between these heterogeneous terminals.

• The Research Journal of the Costume Culture
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• v.28 no.5
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• pp.639-651
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• 2020

This study utilized data to classify and characterize the body types of plus-size adult men aged in their 30s and 40s. Diversity is an important factor in the era of inclusive design, and discussion about size diversity to include the plus size should be accommodated. Data from 493 adult men classified as obese (with a World Health Organization criterion ≥25 BMI) were used for the analysis. The results of the study are as follows. Six independent factors were extracted using factor analysis for cluster analysis, which were then classified into five types. Type 1 (29.01%) was identified as body type I with the smallest degree of obesity. Type 2 (15.4%) was identified as body type Y with wide shoulders and a thin waist. Type 3 (14.2%) was the largest body volume (body type O), while the fourth (19.27%) identified as body type H has a large height and upper body. Lastly, type 5 (22.11%) has a long lower body and a slim abdomen, referred to as body type X. This study presents a basis for the development of various clothing sizes utilizing the body shape characteristics of plus-size men in their 30s and 40s. Follow-up research is needed to develop patterns for plus size men and to design various products.

• The Korean Journal of Ecology
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• v.21 no.5_1
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• pp.409-418
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• 1998

A molel study was conducted to determine the optimal sample size for the analysis of the aquatic insect community in a stream reach of the Pangtae Creek, Kangwon-do in October 1995 and may 1996. The results showed that the required minimum sample size varied and depended on the purposes of the community analysis. Acoording to the Species: Area Curve method, at least 16 Surber samplings ($30{\times}30cm$) were required in a stream reach in each spring and fall survey. The species diversity index did not vary significantly as the sample size increased. Based on the coefficient of variation analysis, the minimum sample sizes of 10 were required in order to compare seasonal differences of the community in the study area. Considering the static community structure of aquatic insects, including both species numbers and individual numbers of aquatic insects, 11 and 7 samplings were optimal sizes for the fall and spring survey, respectively. We concluded that 12 Surber samplings from 3 riffle-pool sequences (4 samplings at each riffle-pool sequence) would be required in a stream reach (length 1 km) to obtain reliable as well as cost efficient data. Our model showed that the optimal sample size should be determined by interactions between minimum sample size, the degree of data reliability, and cost efficiency.

• Computers and Concrete
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• v.28 no.5
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• pp.521-532
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• 2021

Present paper focuses on the modeling of size effect on the compressive strength of normal concrete with the application of Discrete Element Method (DEM). Test specimens with different size and shape were cast and uniaxial compressive strength test was performed on each sample. Five different concrete mixes were used, all belonging to a different normal strength concrete class (C20/25, C30/37, C35/45, C45/55, and C50/60). The numerical simulations were carried out by using the PFC 5 software, which applies rigid spheres and contacts between them to model the material. DEM modeling of size effect could be advantageous because the development of micro-cracks in the material can be observed and the failure mode can be visualized. The series of experiments were repeated with the model after calibration. The relationship of the parallel bond strength of the contacts and the laboratory compressive strength test was analyzed by aiming to determine a relation between the compressive strength and the bond strength of different sized models. An equation was derived based on Bazant's size effect law to estimate the parallel bond strength of differently sized specimens. The parameters of the equation were optimized based on measurement data using nonlinear least-squares method with SSE (sum of squared errors) objective function. The laboratory test results showed a good agreement with the literature data (compressive strength is decreasing with the increase of the size of the specimen regardless of the shape). The derived estimation models showed strong correlation with the measurement data. The results indicated that the size effect is stronger on concretes with lower strength class due to the higher level of inhomogeneity of the material. It was observed that size effect is more significant on cube specimens than on cylinder samples, which can be caused by the side ratios of the specimens and the size of the purely compressed zone. A limit value for the minimum size of DE model for cubes and cylinder was determined, above which the size effect on compressive strength can be neglected within the investigated size range. The relationship of model size (particle number) and computational time was analyzed and a method to decrease the computational time (number of iterations) of material genesis is proposed.

• Journal of the Ergonomics Society of Korea
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• v.31 no.1
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• pp.247-254
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• 2012

Objective: The objective of the study is to analyze adult men's somatotype characteristics, age range from 20s to 50s comparing the direct anthropometric measurement values and to provide the basis information for developing clothing patterns. Background: The comparative study among the age groups is very fundamental to understand the body characteristics of each subjects group. Therefore, comparison of body measurements in age groups was applied in this study. Method: The anthropometric data from the $5^{th}$ Anthropometry of Size Korea(2004) and $6^{th}$ Anthropometry of Size Korea(2010) were applied for the data analysis. Results: As a result, the chest depth/chest width index(the value of chest depth divided by chest width) was increased and the waist depth/waist width index was decreased in all age groups. In addition, the hip depth/hip width index was decreased in age of 20's and 50's. This means that the chest width and hip width were decreased and the waist width were increased. From the data of the 5th Size Korea, the obese men(BMI: 25~30) in the 50s showed the highest percentage of 47.1%, and 44.8% of obese men(BMI: 25~30) in the 40s recorded the highest rate base on the data of the 6th Size Korea. Conclusion: It is concluded that the some differences were showed between the 5th anthropometric data and the 6th data. In particular, obesity tendencies of men in their 20's and 30's were observed significantly compared to other age groups. Application: These findings from the study can be utilized men's wear design and construction that reflect body characteristics.