• Advances in aircraft and spacecraft science
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• v.11 no.1
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• pp.83-103
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• 2024

Adhesive bonding is currently widely used in many industrial fields, particularly in the aeronautics sector. Despite its advantages over mechanical joints such as riveting and welding, adhesive bonding is mostly used for secondary structures due to its low peel strength; especially if it is simultaneously exposed to temperature and humidity; and often presence of bonding defects. In fact, during joint preparation, several types of defects can be introduced into the adhesive layer such as air bubbles, cavities, or cracks, which induce stress concentrations potentially leading to premature failure. Indeed, the presence of defects in the adhesive joint has a significant effect on adhesive stresses, which emphasizes the need for a good surface treatment. The research in this field is aimed at minimizing the stresses in the adhesive joint at its free edges by geometric modifications of the ovelapping part and/or by changing the nature of the substrates. In this study, the finite element method is used to describe the mechanical behavior of bonded joints. Thus, a three-dimensional model is made to analyze the effect of defects in the adhesive joint at areas of high stress concentrations. The analysis consists of estimating the different stresses in an adhesive joint between two 2024-T3 aluminum plates. Two types of single lap joints(SLJ) were analyzed: a standard SLJ and another modified by removing 0.2 mm of material from the thickness of one plate along the overlap length, taking into account several factors such as the applied load, shape, size and position of the defect. The obtained results clearly show that the presence of a bonding defect significantly affects stresses in the adhesive joint, which become important if the joint is subjected to a higher applied load. On the other hand, the geometric modification made to the plate considerably reduces the various stresses in the adhesive joint even in the presence of a bonding defect.

• Journal of Wetlands Research
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• v.21 no.spc
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• pp.98-106
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• 2019

The coefficient and exponent of the MUSLE(Modified Universal Soil Loss Equation) runoff factor in the SWAT(Soil and Water Assessment Tool) model are 11.8 and 0.56 respectively, which are equally applied to the estimation of soil erosion regardless of land use. they could derive overestimation or underestimation of soil erosion, which can cause problems in the selection of soil erosion-vulnerable area and evaluation of reduction management. However, there are no studies about the estimation of coefficients and exponent for the MUSLE runoff factor by land use and their applicability to the SWAT model. Thus, in order to predict soil erosion and sediment behavior accurately through SWAT model, it is necessary to estimate the coefficient and exponent of the MUSLE runoff factor by land use and evaluate its applicability. In this study, the coefficient and exponent of MUSLE runoff factor by land use were estimated for Gaa-cheon Watershed, and the differences in soil erosion and sediment from SWAT model were analyzed. The coefficient and exponent of runoff factor estimated by this study well reflected the characteristics of soil erosion in domestic highland watershed. Therefore, in order to apply the MUSLE which developed based on observed data of US agricultural basin to the domestic watershed, it is considered that a sufficient modification and supplementation process for the coefficient and exponent of the MUSLE runoff factor depending on land use is necessary. The results of this study can be used as a basic data for selecting soil erosion vulnerable area in the non-point source management areas and establishing and evaluating soil erosion reduction management.

• Asia pacific journal of information systems
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• v.18 no.2
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• pp.1-14
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• 2008

According to technology acceptance model(TAN) which is one of the most important research models for explaining IT users' behavior, on intention of using IT is determined by usefulness and ease of use of it. However, TAM wouldn't explain the performance of using IT while it has been considered as a very good model for prediction of the intention. Many people would not be confirmed in the performance of using IT until they can control it at their will, although they think it useful and easy to use. In other words, in addition to usefulness and ease of use as in TAM, controllability is also should be a factor to determine acceptance of IT. Especially, there is a very close relationship between controllability and ease of use, both of which explain the other sides of control over the performance of using IT, so called perceived behavioral control(PBC) in social psychology. The objective of this study is to identify the relationship between ease of use and controllability, and analyse the effects of both two beliefs over performance and intention in using IT. For this purpose, we review the issues related with PBC in information systems studies as well as social psychology, Based on a review of PBC, we suggest a research model which includes the relationship between control and performance in using IT, and prove its validity empirically. Since it was introduced as qa variable for explaining volitional control for actions in theory of planned behavior(TPB), there have been confusion about concept of PBC in spite of its important role in predicting so many kinds of actions. Some studies define PBC as self-efficacy that means actor's perception of difficulty or ease of actions, while others as controllability. However, this confusion dose not imply conceptual contradiction but a double-faced feature of PBC since the performance of actions is related with both self-efficacy and controllability. In other words, these two concepts are discriminated and correlated with each other. Therefore, PBC should be considered as a composite concept consisting of self-efficacy and controllability, Use of IT has been also one of important areas for predictions by PBC. Most of them have been studied by analysis of comparison in prediction power between TAM and TPB or modification of TAM by inclusion of PBC as another belief as like usefulness and ease of use. Interestingly, unlike the other applications in social psychology, it is hard to find such confusion in the concept of PBC in the studies for use of IT. In most of studies, controllability is adapted as PBC since the concept of self-efficacy is included in ease of use explicitly. Based on these discussions, we can suggest perceived use control(PUC) which is defined as perception of control over the performance of using IT and composed of controllability and ease of use as sub-concepts. We suggest a research model explaining acceptance of IT which includes the relationships of PUC with attitude and performance of using IT. For empirical test of our research model, two user groups are selected for surveying questionnaires. In the first group, there are freshmen who take a basic course for Microsoft Excel, and the second group consists of senior students who take a course for analysis of management information by Excel. Most of measurements are adapted ones that have been validated in the other studies, while performance is real score of mid-term in each class. In result, four hypotheses related with PUC are supported statistically with very low significance level. Main contribution of this study is suggestion of PUC through theoretical review of PBC. Specifically, a hierarchical model of PUC are derived from very rigorous studies in the relationship between self-efficacy and controllability with a view of PBC in social psychology. The relationship between PUC and performance is another main contribution.

• Korean journal of food and cookery science
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• v.15 no.3
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• pp.203-209
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• 1999

The effect of several hydrocolloids on the rheological behavior of wheat flour was investigated. The influence of the selected hydrocolloids (alginate, carrageenan, CMC, guar, locustbean and xanthan) on wheat flour was tested by using two different techniques; amylograph and texture analyzer. In order to have a general overview of their effects hydrocolloids were chosen from different sources implying a broad diversity of chemical structures. The hydrocolloid addition decreased the brightness(L) but increased yellowness(b). The interaction between hydrocolloid and flour produces a slight modification of the amylogram parameters, being the most clearly affected parameter breakdown, which is increased by carrageenan, guar and xanthan. Hardness and cutting force were augmented by hydrocolloid addition, while springeness was decreased except guar and locustbean. In summary, when looking for the improvement of the noodle texture, guar, locustbean are the best candidate additives due to their effects on pasting and texture properties. These hydrocolloids increase the hardness, cutting force, gumness, chew-ness, so were thought to increase the eating quality. So, each tested hydrocolloid affected in a different way the rheological properties of wheat flour, the results obtained are important for the appropriate use of these hydrocolloid as ingredients in the noodle making process.

• Journal of Nutrition and Health
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• v.55 no.6
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• pp.642-655
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• 2022

Purpose: We examined the effects of the 8-week moderate-intensity Pilates exercise program on body composition, balance ability, metabolic parameters, arterial condition, and eating habits among overweight and obese women. Methods: From the general sample of overweight or obese Korean women (body mass index ≥ 23 kg/m² ), those who had not been diagnosed with any chronic degenerative diseases were enrolled in the study (n = 39). After 8 weeks of the Pilates exercise program, the participants were subdivided into adherence and non-adherence groups. Among the study participants, 24 women were matched for age and menopausal status to reduce the bias, and then finally included for the comparison (Pilates-adherence, n = 12; Pilates-non-adherence, n = 12). Results: The body balance measured by the Y-balance test, body mass index, and subcutaneous fat areas were significantly improved in both groups. However, the Pilate-sadherence group showed more positive changes in body balance and had significant improvement in body composition parameters such as waist size, visceral fat area, systolic blood pressure, arterial aging index, fasting blood glucose, and glycated hemoglobin than the Pilates-non-adherence group. In addition, the nutrition quotient for Korean adults (balance, moderation, and behavior except diversity) were significantly improved in both groups after dietary education. However, the participants did not show dramatic improvement in the metabolic parameters, because all the study subjects were in relatively good health and did not have any diagnosed diseases. Conclusion: This study demonstrated that higher adherence to the Pilates exercise program together with a modification of eating habits may effectively improve body balance, body composition, and obesity-related parameters among overweight and obese women.

• Journal of the Korean Society of Food Science and Nutrition
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• v.31 no.5
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• pp.847-885
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• 2002

The purpose of this study was to develop a web-based internet program for nutritional assessment and diet Prescription by renal diseases. Renal diseases were classified by nephrotic syndrome, renal failure, hemodialysis and peritoneal dialysis. The system consisted of five parts according to their functions and contents. The first part is to assess the general health status such as body weight, obesity index, basal metabolic rate and total energy requirement by the input of age, sex, height, weight and degree of activity. The second part was designed to investigate dietary history of patient, that is, to find out his inappropriate dietary habit and give him some suggestions for appropriate dietary behavior by investigating his dietary history. This part also offers the diet and nutrition management by personal status with renal disease, and the information for food selection, snacks, convenience foods, dine-out, behavioral modification, cooking methods, food exchange lists and terms. The third part is evaluating their energy and nutrients intake by comparing with recommended dietary allowance for Koreans or standardized data for patient with renal disease. In this part, it is also analyzing energy and nutrients of food consumed by food group and meals, and evaluating the status of nutrient intake. The fort]1 one, a major part of the system, is implementing the diet and menu planning by using food exchange lists. This Part Provides the patient with menus lists and I day menu suitable to his weight, activity and the status of renal disease. The fifth part is providing information on energy and nutrients of foods and drinks, and top 20 foods classified by nutrients. These results are finally displayed as tabular forms and graphical forms on the computer screen.

• Journal of Yeungnam Medical Science
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• v.13 no.1
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• pp.32-45
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• 1996

The AIDS is a serious health problem worldwide today and also in Korea. Increasing knowledge and modification of behavior by health education is an important goal of human immunodeficiency virus(HIV) prevention strategies. And school health education is an important part of health education. This study was conducted to evaluate the knowledge and attitude about AIDS in teachers and professors in Taegu City and to provide the basic data for school health education. A self-administered questionnaire was given to 1,124 teachers and professors from April to June 1992. Indeed, the majority of the teachers and professors have a lot of knowledges about AIDS, but many of them also have misconceptions. The level of knowledge about AIDS was positively associated with attitude toward infected students. The sources of knowledge about AIDS were mainly TV, newspapers and magazines, but a few of the subjects obtained their knowledge from health education programs. This study suggests that the reinforcement of health education for the teachers, professors and students he needed to provide the accurate knowledge on AIDS and adequate knowledge sources and materials for school health education on AIDS should be developed.

• Journal of the Korean Society of Marine Environment & Safety
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• v.25 no.6
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• pp.687-697
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• 2019

By monitoring sediment grain size and level variation of tidal flat surface for 6 years (2005-2011), and also by mooring TISDOS (tidal-flat sediment dynamics observation system) on the low intertidal flat in 2008, we investigated the sedimentary environment of tidal flat in the dammed Yeongsan River Estuary. The tidal flat of the Yeongsan River Estuary lost 82 % of its area because of coastal development projects, and a narrow tidal flat below mean sea level now remains. Most of the tidal flat sediments are composed of silt up to 70-94 %, and show the characteristics of clay deficiency and silt dominance. This is closely related with the coastal development, which led to the destruction of high tidal flats where most mud settled, and the modification of tidal current patterns. Moreover, the estuarine tidal-flat sediments reveal seasonal variation. They are coarse with abundant silt during windy autumn to spring, fine with abundant clay during the less-windy and high-discharge summer. This phenomenon indicates that the behavior of sediment particles on the low intertidal flats of the Yeongsan River Estuary is influenced by wind waves for silt and fresh water discharge and the tidal process for clay. Monitoring results of the altitude of tidal flat surface showed that the study area had eroded at an average rate of -2.6 cm/y during the period of 2005-2011, and also that an unusual deposition with a rate of 4 cm/y occurred in 2010. The erosion can be explained by an increased tidal amplitude and a strengthened ebb-dominant tidal asymmetry after the construction of an estuary dike and the Yeongam Kumho Seawall. The deposition in 2010 seems to have been closely related to the mass production of suspended materials from dredging of the estuary.

• Journal of the Korean Society of Food Science and Nutrition
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• v.33 no.1
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• pp.114-122
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• 2004

The purpose of this study was to develop a web-based internet program for nutritional counseling and diet management of patient with diabetes mellitus. The program consisted of four parts according to their functions and contents. The first part explained the metabolism of glucose and mechanism of insulin and insulin receptor expressed by flash 6.0, and defined the diabetes mellitus. The second part is to assess the general health status such as body weight, obesity index, basal metabolic rate and total energy requirement by the input of age, sex, height, weight and degree of activity. This part also provides tlne patient with menu lists and one day menu suitable to his weight and activity, and offers the information for food selection, snacks, convenience foods, dine-out, behavioral modification, cooking methods, food exchange lists, dietary education using buffet, and information on energy and nutrients of foods and drinks, and top 20 foods classified by nutrients. The third part is designed to investigate dietary history of patient, that is, to find out his inappropriate dietary habit and give him some suggestions for appropriate dietary behavior. This part also offers on-line counseling, follow-up management and frequently asked questions. The fourth part is evaluating their energy and nutrients intake by comparing with recommended dietary allowance for Koreans or standardized data for patient with diabetes mellitus. In this part, it is also analyzing energy and nutrients of food consumed by food group and meals, and evaluating the status of nutrient intake. These results are finally displayed as tabular forms and graphical forms on the computer screen. Therefore it is expected that the web-based internet program developed in this study will play a role in their health promotion as widely using by diabetic patients.

• Journal of Sericultural and Entomological Science
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• v.2
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• pp.1-31
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• 1962

The purpose of this treatise is to prove the presence of cystine in silk fiber through wide sampling throughout all the sericultural processes of Bombyx mori.; also to show that disulfide cross linkages exist in the silk fiber. The conclusions reached were as follows: 1. Crystalline cystine was obtained from silk fibroin using Folin's Method. 2. Analytical data showing the cystine content of silk fiber and its related materials were obtained using Sullvan's Method as follows: Material Percent Cystine A. Mulberry leaf protein 0.175 B. Silkworm egg 0.33 C. Silkworm Body, matured, fat extracted, without silk gland 0.41 D. Silk gland, matured 1.23 E. Silkworm feces none F. Silkworm pupa, fat extracted 0.30 G. Silkworm moth, fat extracted 0.60 H. Raw Silk 0.22 I. Fibroin 0.175 J. Sericin 0.30 3. The presence of cystine in the silkworm was substantiated the existence of 0.175 % methionine in mulberry leaves and 0.12% methionine in the silk gland. 4. Part of the sulfhydryl compounds in the silk gland is believed to transfer to serine and methionine, with the former being secreted into the liquid silk finally as silk fiber and the latter used for nutritive purposes in the growing of silk gland tissue. 5. The cystine content is variable by mulberry species, silkworm species, sex, breeding process, and other culturing environments. 6. Hybrid silkworms require more nutritive amino acids for effective growth than the original parents, and secrete less of them as silk fiber. 7. From such an observation, the amino acid composition of silk fiber is believed to be fairly flexible. Cystine if included in the amorphous part of the fiber, especially in sericin. 8. The result from enriching the silkworm diet with pure cystine or wool cystine did not result in any advantage, therefore it is believed that the natural cystine and methionine contents in the mulberry leafaregoodenoughforsilkwormnutrition. 9. The disulfide cross linkage in silk fiber was verified by using the Harris Method. Contraction took place following the treatment of the fiber with various salts and acids. Comparisons were made with wool fiber. 10. During these experiments, the fibrious structure of silk fiber and the net-globular liquid form were photographed microscopically. It is believed that the globules of liquid silk are net-formed by the inter attraction of the OH ion of the globular peptide and the H ion of water as shown by the hair cracking behavior of the film. The net-globular protein precipitation from the mulberry protein solution showed that mulberry is a proper diet for the formation of fibrous protein in the silk fiber. 11. The significance of the presence of cystine in silk fiber as emphasized in this paper should result in modification of the general conception that cystine is absent from this fiber. NOTICE: A part of this treatise was presented at the annual Korea Sericultural Society meeting held in 1961.