• Proceedings of the Korean Geotechical Society Conference
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• 1999.10a
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• pp.95-102
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• 1999

It is important to estimate the magnitude of settlement and the time of primary consolidation in geotechnical engineering projects. For these purposes, site explorations and laboratory tests are usually performed. However, the mechanical properties determined from laboratory tests on the samples obtained by different sampling techniques show different trends. In this study, three types of consolidation test were carried out on the soil samples obtained by three different sampling techniques (76mm tube, 76mm piston, and block samples), to verify the effect of sample disturbance on consolidation properties. It was found that sampling methods have influence on the $\varepsilon$ - log $\sigma$'$_{v}$ relationship. While insignificant difference of compression indices from the samples obtained by different sampling techniques was observed in compression region, these values showed a different trend in precompression region. The values of $c_{v}$ and k of block samples had a tendency to be larger than those of piston and tube samples. At consolidation pressure larger than $\sigma$'$_{p}$, however, these properties became similar regardless of sampling methods. The block and piston samples gave slightly higher values of $C_{a/}$ $C_{c}$ than tube samples. In the results of I $L_{EOP}$ and CRS test, it was observed that the values of $\sigma$'$_{p measured}$/$\sigma$'$_{p best estimated}$ of Yang-San clay decreases when strain becomes larger than 1.0% and that precompression strain of block samples is in the range of 1.5~2.0% while those of piston and tube samples are 1.75~3.75%. It was also shown that the values of $\sigma$'$_{p}$ of block samples exceed those of piston and tube samples by about 6~10%.6~10%.%.%.%.%.

• Advances in aircraft and spacecraft science
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• v.6 no.6
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• pp.529-550
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• 2019

The effect of multiple process parameters on a set of continuous response variables is, especially in experimental designs, difficult and intricate to determine. Due to the complexity in aeroacoustic and vibroacoustic studies, the often-performed simple one-factor-at-a-time method turns out to be the least effective approach. In contrast, the statistical Design of Experiments is a technique used with the objective to maximize the obtained information while keeping the experimental effort at a minimum. The presented work aims at giving insights on Design of Experiments applied to aeroacoustic and vibroacoustic problems while comparing different experimental designs and approximation models. For this purpose, an experimental rig of a ducted low-pressure fan is developed that allows gathering data of both, aerodynamic and aeroacoustic nature while analysing three independent process parameters. The experimental designs used to sample the design space are a Central Composite design and a Box-Behnken design, both used to model a response surface regression, and Latin Hypercube sampling to model an Artificial Neural network. The results indicate that Latin Hypercube sampling extracts information that is more diverse and, in combination with an Artificial Neural network, outperforms the quadratic response surface regressions. It is shown that the Latin Hypercube sampling, initially developed for computer-aided experiments, can also be used as an experimental design. To further increase the benefit of the presented approach, spectral information of every experimental test point is extracted and Artificial Neural networks are chosen for modelling the spectral information since they show to be the most universal approximators.

• International Journal of Fluid Machinery and Systems
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• v.10 no.3
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• pp.240-253
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• 2017

Latin hypercube sampling is widely used design-of-experiment technique to select design points for simulation which are then used to construct a surrogate model. The exploration/exploitation properties of surrogate models depend on the size and distribution of design points in the chosen design space. The present study aimed at evaluating the performance characteristics of various surrogate models depending on the Latin hypercube sampling (LHS) procedure (sample size and spatial distribution) for a diverse set of optimization problems. The analysis was carried out for two types of problems: (1) thermal-fluid design problems (optimizations of convergent-divergent micromixer coupled with pulsatile flow and boot-shaped ribs), and (2) analytical test functions (six-hump camel back, Branin-Hoo, Hartman 3, and Hartman 6 functions). The three surrogate models, namely, response surface approximation, Kriging, and radial basis neural networks were tested. The important findings are illustrated using Box-plots. The surrogate models were analyzed in terms of global exploration (accuracy over the domain space) and local exploitation (ease of finding the global optimum point). Radial basis neural networks showed the best overall performance in global exploration characteristics as well as tendency to find the approximate optimal solution for the majority of tested problems. To build a surrogate model, it is recommended to use an initial sample size equal to 15 times the number of design variables. The study will provide useful guidelines on the effect of initial sample size and distribution on surrogate construction and subsequent optimization using LHS sampling plan.

• Journal of Korean Society for Quality Management
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• v.17 no.1
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• pp.69-81
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• 1989

This study is concerned with a job sequencing method using the concept of sampling technique in the case of Job Shop. This is the follow study of Kang and Ro (1988) which examined the possibility of application of sampling technique to determine the Job Sequence in the case of Flow Shop. Not only it is very difficult, but also it takes too much time to develop the appropriate job schedules that satisfy the complex work conditions. The most job sequencing algorithms have been developed to determine the best or good solution under the special conditions or assumptions. The application areas of these algorithms are also very narrow, so it is very hard to find the appropriate algorithm which satisfy the complex work conditions. In this case it is very desirable to develop a simple job sequencing method which can select the optimal job sequence or near optimal job sequence with a little effort. This study is to examine the effect of sampling job sequencing which can select the good job of 0.01%~5% upper good group. The result shows that there is the sets of 0.05%~23% job sequence group which has the same amount of performance measure with the optimal job sequence in the case of experiment of N/M/G/$F_{max}$. This indicates that the sampling job sequencing method is a useful job sequencing method to find the optimal or good job sequence with consuming a small amount of time. The results of ANOVA show that the only one factor, number of machines is the significant factor for determining the job sequence at ${\alpha}=0.01$. It takes about 10 minutes to compare the number of 10,000 samples of job sequence by personal computer and it is proved that the selection rate of the same job sequence with optimal job sequence is 23.0%, 3.9% and 0.065% in the case of 2 machines, 3 machines and 4 machines, respectively. The area of application can readily be extended to the other work condition.

• The Journal of Korean Academic Society of Nursing Education
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• v.12 no.2
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• pp.265-271
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• 2006

Purpose: To analyze the newly developed vacuum assisted auto-lancing technique applied to the forearm for the purpose of obtaining an adequate blood sample for glucose test with minimal pain. Methods: Visual and facial pain measures were introduced to compare lancing pain between the forearm and fingertip in 58 normal females. Sampled blood volumes were accurately measured by computer scanning technique. Results: Visual pain measure demonstrated significant pain reduction effect of the forearm sampling compared with the traditional fingertip sampling, which was also consistent with facial pain measure results. Blood volume more than $0.5{\mu}L$, enough for blood glucose testing with modern glucometers, was collected in 399(86%) of 464 forearm samples. Conclusions: Capillary blood sampling could be performed with minimal pain on the forearm by the newly developed vacuum assisted auto-lancing technique. With some resampling when necessary, the forearm sampling seemed very useful, considering almost no pain felt by the patients.

• Food Science of Animal Resources
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• v.21 no.2
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• pp.149-155
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• 2001

The aims of this study were to examine contamination sources and provide the basic data in establishment of sanitary standard for raw pork meat. From \"Random sampling(I)\", initial total plate counts of post-slaughter samples for the group A, B and C were 1.5${\times}10^4$cfu/$textrm{cm}^2$, 5.5${\times}10^5$cfu/$textrm{cm}^2$ and 1.8${\times}10^4$cfu/$textrm{cm}^2$, respectively, and of post-prechilling samples for the group A, B and C were 1.0${\times}10^4$cfu/$textrm{cm}^2$, 4.6${\times}10^5$cfu/$textrm{cm}^2$ and 2.5${\times}10^4$cfu/$textrm{cm}^2$, respectively. Initial total plate counts of post-transportation samples for the group D, E and F did not increased, as did the group A, B and C. From \"Normal sampling(II)\", initial total plate counts of post-slaughter, post-prechilling, post-transportation and post-2 days preservation samples were 7.3${\times}10^4$cfu/$textrm{cm}^2$, 9.6${\times}10^4$cfu/$textrm{cm}^2$, 2.0${\times}10^5$cfu/$textrm{cm}^2$ and 2.5${\times}10^5$cfu/$textrm{cm}^2$, respectively. From \"Clean sampling(III)\", initial total plate counts of post-slaughter, post-prechilling, post-transportation and post-2 days preservation samples were decreased to 7.0${\times}10^2$cfu/$textrm{cm}^2$, 7.5${\times}10^2$cfu/$textrm{cm}^2$, 8.5${\times}10^2$cfu/$textrm{cm}^2$ and 5.5${\times}10^3$cfu/$textrm{cm}^2$, respectively, compared with "Normal sampling(II)". No E. coli O157:H7, Staphylococcus aureus and Salmonella were detected at each sampling step. Consequently, a slaughter method like "Clean sampling(III)" showed a better sanitary effect to low total plate counts of 10$^2$∼10$^3$times, compared with "Normal sampling(II)". The one of contamination sources for raw pork meat was at a slaughtering step, and "Clean sampling" method may be considered as the one of sanitary standards.

• Survey Research
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• v.8 no.2
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• pp.67-89
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• 2007

The Korea National Health and Nutrition Examination Survey(KNHANES) consists of Health Interview Survey, Health Behaviour Survey, Nutrition Survey, and Health Examination, and is designed to produce a broad range of descriptive health and nutritional statistics for sex and age subdomains of the population. These data can be used to measure and monitor the health and nutritional status of the population of Korea. The survey has been conducted three times from 1998. The Korea Centers for Disease Control and Prevention(KCDC) is preparing for the 4th survey which is to be conducted from 2007 through 2009. This study is to design a sample for the 4th survey. The main new feature of the sampling design is using a rolling sampling design method. Since KCDC has imposed some operational requirements, e,g., the needs of producing the annual national statistics and of year-round data collection by some regular staffs, a rolling sampling design method is introduced. This is the first time in history of applying a rolling sampling design for a national-wide large scale survey in Korea. Bringing in the rolling sampling, measurement variation due to different data collectors may be minimized.

• The Journal of Asian Finance, Economics and Business
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• v.7 no.6
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• pp.427-437
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• 2020

This study seeks to examine empirically the effect of leadership style on organizational commitment and organizational effectiveness. The data are from all departments of the undergraduate program at the State University in Central Java, Indonesia. The study comprises all divisions of the undergraduate program, which amounted to 207 people. The method for sampling is based on simple random sampling. Structural equation modeling (SEM) is applied in order to analyze the data. The results show that integrative adaptive leadership style has a positive effect on teamwork and affective commitment. Therefore, in order to improve teamwork, the organization should be assisted in completing the introduction of collaborative conflict resolution. Moreover, affective commitment positively affects organizational effectiveness. Thus, it can be said that efforts to improve the organizational effectiveness, should be supported by affective commitment. The study further revealed that integrative adaptive leadership style has a positive effect on teamwork. This means better execution of integrative adaptive leadership, higher level of coordination and vice versa. Each member has different responsibilities and duties, and it can be done or resolved in different ways. If the leader can accommodate the creativity of the faculty and staff, a solid team can be formed.

• ETRI Journal
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• v.40 no.3
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• pp.366-375
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• 2018

Recently, techniques involving head-mounted displays (HMDs) have attracted much attention from academia and industry owing to the increased demand for virtual reality and augmented reality applications. Because HMDs are positioned near to users' eyes, it is important to solve the accommodation-vergence conflict problem to prevent dizziness. Therefore, holography is considered ideal for implementing HMDs. However, within the Nyquist region, the accommodation effect is limited by the space-bandwidth-product of the signal, which is determined by the sampling number of spatial light modulators. In addition, information about the angular spectrum is duplicated over the Fourier domain, and it is necessary to filter out the redundancy. The size of the exit-pupil of the HMD is limited by the Nyquist sampling theory. We newly propose a holographic HMD with an expanded exit-pupil over the Nyquist region by using the time-multiplexing method, and the accommodation effect is enhanced. We realize time-multiplexing by synchronizing a high-speed digital micromirror device and a liquid-crystal shutter array. We also demonstrate the accommodation effect experimentally.

• Korean Journal of Human Ecology
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• v.16 no.2
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• pp.349-365
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• 2007

The purpose of this study was to explore the Korean housewives' consumption experiences and perceived quality of life. Perceived quality of life was composed of four dimensions: motivation, affect, efficiency, and activation. The study results are: 1. Housewives spare their time for physiologic activities(22.9%), household activities(20.1), and personal activities(10.1%) in sequence. 2. Although the motivation that housewives do shopping activities is coming from a sense of duty, the perceived quality of life during shopping is showing far more positive affect than the perceived quality of life during other activities. In this context, shopping activities are interesting in that they are thought of a kind of entertainment as well as work. 3. With an analysis of covariance, housewives' perceived quality of life has an effect on everyday life in that 4 perceived qualities of life such as motivation, affect, efficiency and activation has a significant effect on flow and it has a significant effect on satisfaction.