• Advances in aircraft and spacecraft science
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• v.9 no.3
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• pp.195-215
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• 2022

The increasing interest in CubeSat platforms ant their capability of enlarging the frontier of possible missions impose technology improvements. Miniaturized electrical propulsion (EP) systems enable new mission for multi-unit CubeSats (6U+). While electric propulsion systems have achieved important level of knowledge at equipment level, the investigation of the mutual impact between EP system and CubeSat technology at system level can provide a decisive improvement for both the technologies. The interaction between CubeSat and EP system should be assessed in terms of electromagnetic emissions (both radiated and conducted), thermal gradients, high electrical power management, surface chemical deposition, and quick and reliable data exchanges. This paper shows how a versatile CubeSat Test Platform (CTP), together with standardized procedures and specialized facilities enable the acquisition fundamental and unprecedented information. Measurements can be taken both by specific ground support equipment placed inside the vacuum facility and by dedicated sensors and subsystems installed on the CTP, providing a completely new set of data never obtained before. CTP is constituted of a 6U primary structure hosting the EP system, representative CubeSat avionics and batteries. For the first test campaign, CTP hosts the ambipolar plasma propulsion system, called Regulus and developed by T4I. After the integration and the functional test in laboratory environment, CTP + Regulus performed a Test campaign in relevant environment in the vacuum chamber at CISAS, University of Padua. This paper is focused on the test campaign description and the main results achieved at different power levels for different duration of the firings.

• Proceeding of Spring/Autumn Annual Conference of KHA
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• 2006.11a
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• pp.310-315
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• 2006

Recently, an apartment has been changed to be high and diverse. In addition, it has been popularized rapidly. The more number of residents are increased, the more danger of the fire is also increased. If residents are in the upper floor when a fire breaks out, they have much longer evacuation path than the usual. What is more, their condition becomes more unstable. so, riskiness of evacuation is very serious. We should set up environment of evacuation safely. Even though some evacuation system is set up , the dangerous situation is more likely to be occurred. Because it depend on the person. If the person in the building don't recognize that system, it's valueless. Therefore it's very important to understand residents' conciousness level which is related to flee for safety in the fire. In this study, we examine into residents' aware safety level by their residential type. And according to this data, let residents know how they escape from danger . As a result, they can get out of danger when a fire breaks out.

• Transactions on Electrical and Electronic Materials
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• v.15 no.3
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• pp.144-148
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• 2014

The purpose of this research is to utilizing the Tetrax$^{(R)}$ balance measuring instrument in order to analyze the postural balance of males and females in their 30 s diagnosed with chronic lower back pain who have followed a 12-week rehabilitation exercise program. The research also examines the effects on any change in back pain level. In terms of the variables in this research, postural balance (left/right, front/back, postural balance) and pain level change (0~100 mm) were measured. Pre-/post-experimental differences were assessed using the paired-t test. In addition, to identify any gender gap, we set the preliminary scores as a covariate and ran the Analysis of Covariance. Statistical significance (a) herein was set at 0.05. As a result of this research experiment, the left/right, front/back, and overall postural balance were found to increase in both the male and female cases, but with no statistical significance or gender gap. However, both males and females showed a significant decrease in their back pain levels. These findings demonstrate the necessity of continuing clinical research based on the Tetrax$^{(R)}$ equipment for scientific evaluation of the effects of rehabilitation exercises on chronic lower back pain patients and their balancing ability.

• The Journal of Korean Physical Therapy
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• v.31 no.4
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• pp.193-198
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• 2019

Purpose: This study examined the effects of plank exercise combined with breathing and arm exercises on the external oblique, internal oblique, and transverse abdominal muscle thickness. Methods: Thirty healthy adults consisting of 12 males and 18 females from K area were divided into a plank exercise combined with breathing and arm exercises group (n = 15) and a plank exercise only group (n=15). The changes in muscle thickness before the exercise and four and eight weeks after the exercise were analyzed using a two-way repeated analysis of variance (ANOVA). The significance level was set to ${\alpha}=0.05$. Post-hoc t-tests were conducted to detect the interactions between the time and groups, and the significance level was set to ${\alpha}=0.01$. Results: According to the experimental results, the external oblique abdominal muscle showed significant differences over time (p<0.05). The internal oblique abdominal muscle also showed significant differences over time and in the interactions between the time and groups (p<0.05). The transverse abdominal muscle showed significant differences over time, in the interactions between time and groups, and in the changes between the groups (p<0.05). Conclusion: The results indicated that plank exercise combined with breathing and arm movement exercises led to increases in the abdominal muscle thickness. These types of exercises may be useful in lumbar stabilization rehabilitation treatment.

• Proceedings of the KIEE Conference
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• 2002.11c
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• pp.521-524
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• 2002

This paper deals with the rule generation from data for control system and data mining using rough set. If the cores and reducts are searched for without consideration of the frequency of data belonging to the same equivalent class, the unnecessary attributes may not be discarded, and the resultant rules don't represent well the characteristics of the data. To improve this, we handle the inconsistent data with a probability measure defined by support, As a result the effect of uncertainty in knowledge reduction can be reduced to some extent. Also we construct the rule base in a hierarchical structure by applying core as the classification criteria at each level. If more than one core exist, the coverage degree is used to select an appropriate one among then to increase the classification rate. The proposed method gives more proper and effective rule base in compatibility and size. For some data mining example the simulations are performed to show the effectiveness of the proposed method.

• ETRI Journal
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• v.43 no.4
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• pp.746-757
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• 2021

Side-channel attacks pose an inevitable challenge to the implementation of cryptographic algorithms, and it is important to mitigate them. This work identifies a novel data encoding technique based on 1-of-4 codes to resist differential power analysis attacks, which is the most investigated category of side-channel attacks. The four code words of the 1-of-4 codes, namely (0001, 0010, 1000, and 0100), are split into two sets: set-0 and set-1. Using a select signal, the data processed in hardware is switched between the two encoding sets alternately such that the Hamming weight and Hamming distance are equalized. As a case study, the proposed technique is validated for the NIST standard AES-128 cipher. The proposed technique resists differential power analysis performed using statistical methods, namely correlation, mutual information, difference of means, and Welch's t-test based on the Hamming weight and distance models. The experimental results show that the proposed countermeasure has an area overhead of 2.3× with no performance degradation comparatively.

• Journal of applied mathematics & informatics
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• v.41 no.3
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• pp.657-685
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• 2023

This paper aims to apply the concept of Pythagorean fuzzy soft sets (PFSSs) to UP-algebras. Then we introduce five types of PFSSs over UP-algebras, study their generalization, and provide illustrative examples. In addition, we study the results of four operations of two PFSSs over UP-algebras, namely, the union, the restricted union, the intersection, and the extended intersection. Finally, we will also discuss t-level subsets of PFSSs over UP-algebras to study the relationships between PFSSs and special subsets of UP-algebras.

• Journal of Bio-Environment Control
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• v.11 no.4
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• pp.157-162
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• 2002

The efficient timer-controlled irrigation and the favorable fruiting position were investigated far highly quality melon fruits from Feb.18 to July Si 1999. The nutrient solution was supplied either at every hour from 6：00 to 18：00 (T-1) or at 6：00, 8：00, 10：00, 11：00, 12：00, 12：30, 13：00, 13：30, 14：00, 14：30, IS：00,16：00, and 17：00 (T-2). A fruit was set at the first node of the fruit bearing branch from the 10, 12, or 13th node of the main stem. Pot weight was maintained at almost n constant level, regardless of the daily integrated solar radiation in T-2. Soluble solids content (SSC) and fresh weight of fruit were not significantly different among the irrigation treatments at each harvesting time. At the first harvest, SSC and fresh weight of fruit were not significantly different between the fruiting positions within the irrigation treatment. At the second harvest, SSC was higher in T-2 than T-1. The SSC was low in the fruit of the loth node in T-1, while it was not significantly different between fruiting positions in T-2. Fruit fresh weight was the highest at the 12 and 13th nodes in T-1, and the 13th node in T-2. Fresh and dry weights of leaf except petiole, regardless of harvesting time, increased as the node position was higher, The higher the fruiting position was, the lower the leaf weight was. Therefore, it is recommended to irrigate more frequently during the mid-noon. Fruits can be harvested earlier at the lower nodes in the spring crop production.

• Journal of the Korean Home Economics Association
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• v.35 no.1
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• pp.429-442
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• 1997

This study present s and tests a casual model of cohesion adaptability the level of stress recognition coping starategies and quality of life for employed wives and unemployed wives. For the data set 205 employed wives and 200 unemployed wives living in Pusan were chosen. The data were analyzed using M, SD, t-test multiple regression and path analysis. The findings of this study are as follows; First There level of stress recognition and quality of life are higher for employes wives than unemployed wives. Cohesion is higher for employed wives. Whereas adaptability is higher for unemployed wives than employed wives. Employes wives are greater use of coping starategies than unemployed wives. Second For employes wives adaptability the level of stress recognition and coping starategies have significant direct effect on quality of life. Besides wife's level of education age of the youngest child working hours employment motivation and cohesion have significant indirect effect on quality of life. For unemployed wives cohesion adaptability and level of stress recognition have signficant direct effect on quality of life. Besides wife's level of education number of children religion and husband's housework participation are indirectly associated with quality of life. From these results the proposed model is generally supported by the data.

• Journal of the Korean Home Economics Association
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• v.35 no.2
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• pp.33-47
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• 1997

The purpose of the study is to examine the differences between rural and urban in the factors and the level of stress in adolescent, inner control and communication with parents. Also, It is to research the influence of environmental variables, inner control and communication with parents on adolescent's stress in sides of rural and urban. Therefore, I provide needed data in instructing students. For the data set, academic high school students in second grade in a town for rural and Su-Seung gu, Dal-Sugu, chung gu in Dae-gu for urban were chosen. The data were analyzed with the frequency, percentage, factor analysis Mean, S.D, reliability, t-test, regression in use of Spss PC+ Program. The main results are as follow. First, for rural students, stress level is displayed studies, future0affair, life-attitude, companions, self-assurance and home life in order by lower sphere. For urban students, it is displayed future-affair, studies, life-attitude, companions, self-assurance and home life in order by lower shpere. In case of rural "I don't know effective study method" is highly displayed by factors. In case of urban. "I am tired of a competitive life" is highly displayed. The mean of stress level is 3.22 for rural and 3.07 for urban. The differences between rural and urban are showed in self-assurance, studies and companions. Finally when we see the stress generally the stress level is higher in rural high school students than in urban high school students. Second, rural students are lower displayed than urban students in inner control and communication with parents. There is no difference urban students in inner control and communication with parents. There is no difference in communication with a mother. third, influential variables on stress level are inner control, communication with parents, satisfaction with companions and school life as environmental variables in sides of rural and urban. Physical condition is added for rural and sex for urban Finally we get the result that stress level is high in low inner control, poor communication with parents, bad companions and unsatisfied school life for both rural and urban. Bad physical condition for rural and female for urban are added.