• The Korean Journal of Applied Statistics
• /
• v.19 no.2
• /
• pp.231-240
• /
• 2006

It is well understood that a paired comparison (paired t test) provides better precision than a group comparison (two-sample t test), when the pairing is effective (the variation within a pair is small). However, when the variation among the pairs is sufficiently small, the group comparison is likely to yield a better result. To get a statistical explanation of this, we examine the two methods through an analogy to one-way and two-way analysis of variance. We introduce a new measure, R statistic, which is the ratio of their confidence interval lengths, as a quantitative criterion for comparing the two methods. The distribution of the Rf statistic is described by t and F distribution functions. Through this characterization, we show that the paired comparison can be better than group comparison when the variation among the pairs is statistically significantly large.

• International Journal of Internet, Broadcasting and Communication
• /
• v.12 no.4
• /
• pp.61-70
• /
• 2020

As mobile device usage time increases thanks to the development of information and communication alongside the increase in the spread of smartphones, mobile shopping has become a common trend. While mobile shopping has the advantage of saving both time and money, it may also result in dissatisfaction with product differences after purchase. For online clothing shopping malls, in particular, if the size does not match after purchase, it is difficult for customers to return or exchange the goods. To address this problem, some mobile apparel shipping malls offer a virtual fitting service and a size comparison function; however, the number of such malls remains low. In this paper, a usability evaluation was performed on a mobile apparel shopping mall that provides a size comparison function. The three apps selected for evaluation have different size input methods, and a slightly different method of providing results after comparing the user's dimensions with the dimensions of the clothes to be purchased. In this paper, the evaluators were asked to select clothes at the shopping mall and perform the task of deciding the size of the clothes to be purchased through their own measurements and comparison while also evaluating the effectiveness, meaning, and satisfaction of the apps. Based on the analysis of the results, this paper aims to produce an improvement plan and help design the size comparison UI (User Interface) in the future.

• Journal of Korean Physical Therapy Science
• /
• v.10 no.1
• /
• pp.74-82
• /
• 2003

The purpose of this study is to provide guideline of muscle strengthening exercise for preparing ambulation by presenting suitable ratio of muscle power of agonist & antagonist, and that of concentric & eccentric contraction on behalf of amputee's normal ambulation training and it's strenthening as well. 7 Subjects who have femur amputee for experimental group were able to ambulate naturally without inconvenience and 20 adult subjects of comparison group for comparison were considered to be free from disturbance of ambulation. The method of study was to measure the muscle power of hip pint, was to figure out the ratio of agonist & antagonist, concentric contraction & eccentric contraction, and was to find out mean and standard deviation of each measurement. Every numerical value of comparison was tested by Mann-whitney and comparison group's comparison between left & right value was done with t-test. Results are as followings : 1) Extension force was stronger than flexor force and had no remarkable difference(p<0.05) 2) For normal adults, adduction farce was stronger than abduction force and for amputees, abduction force was stronger while adduction force was the same as the normal without showing remarkable difference(p<0.05) According the result above, I make an assumption that maintaining a proper ratio of muscle power on strengthening exercise for amputee's ambulation training & rehabilitation and finally bring out an improvement of transfer and ambulation.

• Journal of Power Electronics
• /
• v.9 no.4
• /
• pp.553-566
• /
• 2009

In-phase control and energy-optimized control are the two major control strategies proposed for series power quality controllers (SPQC). However quantitative analysis and comparison between these two control strategies is quite limited in previous publications. In this paper, an extensive quantitative analysis is carried out on these two control strategies through phasor diagram approach, and a detailed quantitative comparison is conducted accordingly. The load current is used as the reference phasor, and this leads to a simpler and clearer phasor diagram for the quantitative relationship. Subsequently detailed analysis of SPQC using in-phase control and energy-optimized control are provided respectively, under different modes both for under voltage/voltage sag and for over voltage/voltage swell. The closed form analytic expressions and the curves describing SPQC compensation characteristics are obtained. The detailed system power flow is figured out for each mode, and the detailed quantitative comparison between the two control strategies is then carried out. The comparison covers several aspects of SPQC, such as required compensating voltage magnitude, required capacity of energy storage component, and maximal ride-through time. In the end, computer simulation and prototype experimental results are shown to verify the validity of all the analysis and the result of the comparison.

• Journal of Sensor Science and Technology
• /
• v.31 no.6
• /
• pp.448-454
• /
• 2022

An intralaboratory comparison of the realization of the triple-point temperature of mercury, which is defined as -38.8344℃ on the international temperature scale of 1990 (ITS-90), was conducted at the Korea Research Institute of Standards and Science (KRISS), the national metrology institute of Korea. To this end, four triple-point-of-mercury cells were compared using the resistance ratio measurement of a standard platinum resistance thermometer to validate the calibration results obtained using the triple-point-of-mercury cells at KRISS. The triple-point temperatures of all the four cells, one of which is designated as the national standard cell, were within 0.3 mK of the national standard. Based on 13 experiments on the four triple-point-of-mercury cells, the uncertainty in the comparison of the triple-point-of-mercury cells was 0.08 mK, and the uncertainty in the realization of the triple-point temperature of mercury was 0.19 mK. The results of the intralaboratory comparison validated that utilizing any of the four triple-point-of-mercury cells would result in the realization of a temperature within 0.3 mK of the average value determined by two key international comparisons for the realization of -38.3844℃ following the ITS-90.

• Journal of Korean Academy of Nursing
• /
• v.32 no.6
• /
• pp.888-896
• /
• 2002

The purpose of this study wsa to necessitate auricular acupressure therapy as an independent nursing intervention on cancer paitents by confirming its effectiveness. Method: The experimental study was unequivalently controlled pre-post measure study. The subjects were 40 cancer patients who were hospitalized in K medical center in Seoul. The experimental group (20) and the control group (20) were randomly assigned. As measured tools, Spielberger's State-trait Anxiety (1976) measured tool by Kim's transplation (1978). The auricular acupressure therapy was applied to experimental group, and the pre-post measure was performed to both group. The data was analyzed by using SPSS computer program that included descriptive statistics, 2-test, and t-test. Result: 1) The experimental group with the auricular acupressure therapy showed lower trait anxiety scores in comparison with the control group (t= 8.036, p=.000). 2) The experimental group which applied the auricular acupressure therapy showed lower state anxiety scores in comparison with the control group (t= 19.616, p=.000). This result showed that cancer patients with the auricular acupressure therapy applied cancer patients decreased state anxiety and trait anxiety. Therefore , effectiveness of the auricular acupressure therapy was confirmed through this study. Conclusion: According to the result, anxiety of cancer pateint should be decreased and controlled by the auricular acupressure therapy as independent nursung intervension. In addition, the auricular acupressure therapy will provide effective independent nursing intervention that will decrease anxiety on patient with other disease and will improve quality of their lives.

• Proceedings of the Korean Geotechical Society Conference
• /
• 2008.03a
• /
• pp.1216-1223
• /
• 2008

Displacement control of earth retaining wall is recognized as the most important item for insuring the stability of ground in urban deep excavation site near by major structure such as subway etc. The field monitoring system is classified by two types as manual system and automatic system. The application case of latter type of field monitoring is increased because real time measurement is possible in automatic system and that is correspondent with the recent constructional trend. Though the automatic monitoring system is more useful and advanced than manual monitoring system, accuracy of the system is not verified sufficiently. It was examined that the reliance of automatic monitoring system in this paper through the comparison of monitoring result obtained three urban excavation site in which the each type of monitoring system was executed concurrently. Result of the examination is that the two types of monitoring system is generally alike in view of monitoring result, so the engineering reliance of automatic system was confirmed in case site. This task was researched in restricted case site, it is expected more precise analysis from security of more data monitored and progressive study.

• Journal of Magnetics
• /
• v.19 no.1
• /
• pp.28-31
• /
• 2014

The aim of the present study was to examine whether mirror therapy, in conjunction with repetitive transcranial magnetic stimulation (rTMS), can improve the upper extremity function of stroke patient. This study was conducted with 35 subjects, who were diagnosed as a hemiparesis by stroke. The Mirror plus rTMS group was of 12 members who undertook mirror therapy in conjunction with rTMS, the Mirror group was of 11 members who undertook mirror therapy, and the control group was of 12 members who undertook sham therapy. A motor cortex excitability was performed by motor evoked potential, and upper limb function was evaluated by Fugl-Meyer Assessment, and Box and Block Test. Significant difference was shown after the experiment, in comparison of the groups in terms of latency, and as the result of post hoc test, significant difference was shown between the Mirror plus rTMS group and control group, and between the Mirror group and control group, respectively. Significant difference was shown after the experiment in comparison of the groups in amplitude, and as the result of post hoc test, significant difference was shown between the Mirror plus rTMS group and Mirror group, and between the Mirror plus rTMS group and control group. Significant difference was shown after the experiment, in comparison of the groups in FMA and BBT, and as the result of post hoc test, significant difference was shown between the Mirror plus rTMS group and Mirror group, and between the Mirror group and control group. The study showed that mirror therapy in conjunction with rTMS is more effective to improve upper extremity function, than mirror therapy and sham therapy.

• Journal of the Korea Fashion and Costume Design Association
• /
• v.8 no.3
• /
• pp.113-117
• /
• 2006

The main objective of this study is to provide numerical guideline for the development of educational environment about girls in the adolescent period ($14{\sim}16\;years$) through comparison and analysis on physical standards of nation (report published in 1997). The sample for this work was chosen from data which were collected and measured by Size Korea during two years ($2003{\sim}2004$). In order to analyze feature of the somatotype of girls in the adolescent period, analysis was performed about 858 subjects on 22 body parts such as height (6 parts), width (3 parts), thickness (3 parts), circumference (4 parts), length (5 parts) and body weight. For the specific comparison on somatotype, $R\'{o}hrer$ index and Mollison's comparison graph were used. The result of this study enables us to know the important factors which affect the somatotype of girls in the adolescent period ($14{\sim}16\;years$) and will be utilized in various fields such as design of classroom, student uniforms, facilities and equipments for education, etc. According to the result of this study, future research will be focused on not only development of educational facilities but also uniform patterns of female students. In addition, the research on development of equipments which are being used by girls in the adolescent period ($14{\sim}16\;years$) will be another future research.

• Transactions of the Korean Society of Automotive Engineers
• /
• v.19 no.4
• /
• pp.64-71
• /
• 2011

Homogeneous charge compression ignition (HCCI) was the best concept able to provide low NOx and PM in diesel engine emissions. This new alternative combustion process was mainly controlled by chemical kinetics in comparison with the conventional combustion in internal combustion engine. In this paper, detailed kinetic reaction mechanisms of diesel surrogate was investigated to understand the diesel HCCI engine combustion. It was tested two existing mechanisms and two new mechanisms for the comparison of experimental result. The best mechanism for diesel surrogate was suggested through this comparison.