• KSBB Journal
• /
• v.11 no.4
• /
• pp.481-488
• /
• 1996

In spite of diverse applications of chitin derivatives, commercial use of chitin has been limited due to highly resistance to chemicals and the absense of proper solvents. One of methods to reduce such high resistance to chemicals is to make microcrystalline chitin(MCC) by hydrolysis of chitin. Presently, MCC is produced mainly by using high concentration of acid, but this treatment requires an extensive posttreatment to remove or recover acid. An alternative process for MCC production was developed by using dilute hydrochloric acid with ultrasound and hydrogen peroxide. The major parameters for this process were found to be acid concentration, swelling time and temperature, and irradiation time and frequency of ultrasound. The effects of these parameters on MCC molecular weight were investigated. The molecular weight of MCC produced at a typical condition was around 30,000 which was approximately 1/8 of that of chitin and approached to a constant value. This phenomenon was explained by introducing the model of molecular arrangement of cellulose. SEM analysis showed that both chitin and MCC had a fibrous shaped morphology and the fibril size of MCC was much smaller than that of chitin.

• Archives of design research
• /
• v.19 no.4 s.66
• /
• pp.101-110
• /
• 2006

In this study, I suggested a new model of universal web navigation design which can enhance users' web usability. I would like to prove that when users enjoy web navigation design, they access information much more effectively. Using a survey, I suggest some types of web navigation design for users. After that, I conducted an experiment with 4 types of web navigation designs, which have been developed to reflect varying stages of comprehensibility. My survey focused on three points. First I measured the time they spent to search for information. Second, I tested whether they lost their way while searching for information and if they did lose their way, I checked whether they could recover from their errors and find their way back. Third, I investigated whether layout, location and size of the web navigation design factors affected usability. The results of my survey indicated that users spend the shortest time, have the easiest interface, and have least error incidence under the web navigation design to enhance old-aged users' web usability. Thus, developing a universal web navigation design can encourage people to be more involved with the internet.

• Journal of the Korean Society of Food Culture
• /
• v.13 no.2
• /
• pp.127-134
• /
• 1998

A survey was carried out to investigate into high school girls' food intake pattern and their behavior for weight control. The average height and weight of the subjects were 161cm and 52.9kg, while 53.3% of them usually had breakfast which 83.7% of them had steamed rice and dishes,64.7% of residue (46.7%) them often skipped breakfast because they didn't have to eat. Most of them had lunch which prepared from home at lunch time (75.7%), they cheesed foods at first by taste(71.9%), but they almost didn't consider the nutritional aspects, also they had very small amount of fruits and vegetables. They had snack more than once a day(93.4%), As snack, they used mainly cookies(39%), Ramyun and Ddukbocki(31.5%),and breads(17.6%). Meal time was shown to be short such as 10 or 20 minutes(40.7%), dinner was thought to be the most important meal(66.9%) In spite of their weight was standard(56.68%), they thought their style as fatty(48.1%) and they wanted to reduce weight(90.4%). 90.3% of all subjects were interested in weight control and students with standard sizes(52.7%) and/or/(p<0.05) lean weights(27 1%) had concerning about weight control significantly. The motive of attempt to weight control was shown to be effected by mass communication(49.1%) mainly, When they tried to lose their weight, 66.7% of them depended on their own judgement, while only 1.1% asked for the advice of a doctor. The most effective way to control weight was thought to increase the amount of exercise(52.7%) and to control the amount of food (32.2%).

• Korean Journal of Medicinal Crop Science
• /
• v.9 no.4
• /
• pp.259-264
• /
• 2001

This experiment was conducted to examine the seed structure and to investigate the changes of seed vigor and germinability according to storage condition of Astragalus membranaceus. In case of the hard seed, there observed a gap between a testa and an embryo with abnormal shapes of an hilum and its micropyle. Seeds stored at room temperature maintained vitality for 4 months but continued to lose its vitality, while increase the hand seeds ratio as storing time longer. The content of Ca increased in proportion to the length of storing time.

• Journal of the Society of Naval Architects of Korea
• /
• v.46 no.1
• /
• pp.78-86
• /
• 2009

A capacity calculation and process analysis is a very important part for the entire ship production planning. Ship's production plan is set up with a concept that the product is produced based on the capacity achievable by the processes while general manufacturing sets up the production plan based on product lead-time. Therefore, in case the calculation of capacity for each process of shipbuilding yard is different from actual conditions, a series of production plan - ship table composition, dual schedule plan and execution schedule plan, etc - may accumulate errors, lose reliability of planning information and cause heavy cost deficit in this course. In particular, in case of new shipbuilding yard, stocks between processes are built up and half blocks are not supplied in timely manner, and that is sometimes due to the clumsiness of the operator but it is more often because of the capacity to execute each process is not logically calculated. Therefore, this paper presents the process to calculate the assembly leadtime and assembly process capacity for shipbuilding yard assembly factory. This paper calculated the block type for calculation of assembly lead time based on block DAP(detailed assembly procedure), and introduced cases that calculate production capacities by assembly surface plate by considering the surface plate occupied area of the blocks that change depending on assembly field area and assembly processes through assembly simulation.

• Korean Journal of Community Nutrition
• /
• v.8 no.6
• /
• pp.856-866
• /
• 2003

The purpose of this study was to study the relationship between the prevalence of constipation and beverage intake. Research data were collected from first and second grade female students at Hyehwa High School in Seoul by means of questionnaires. A total of 190 questionnaires were analyzed using the SPSS/WIN program. The results are summarized as follows: The average body mass index (BMI) was 20.7. Of the students, 38.4% had a BMI of less than 20(underweight), and 15.8% had a BMI of over 23 (overweight). However, 84.7% of the students wanted to lose weight. To estimate the prevalence of constipation, five factors were used: frequency and regularity of defecation, time spent defecating, defecation difficulty, and feeling of residue after defecation. The percentage of the students who emptied their bowels every day was 22.1%. About 2/5 of the students (42.1%) had irregular defecation, and 15.2% spent more than 10 minutes in the rest room when defecating. The students who did not have difficulty defecating and those who did not have feelings of residue after defecating were only 24.7% and 28.9%, respectively. The amount of beverage intake per day was 1,062$m\ell$ 674$m\ell$ of water, 128$m\ell$ of milk, 88$m\ell$ of soft drinks, and 53$m\ell$ of fruit juice. The amount of beverage intake before breakfast, during breakfast, before lunch and during lunch was about 100 $m\ell$, each; before dinner, during dinner, and after dinner it was about 200$m\ell$, each. The amount of beverage intake during the weekend was 120$m\ell$ greater than on weekdays. Students who drank more beverages, especially water, before breakfast, showed a higher defecation frequency, more regular defecation, spent less time defecating, had less difficulty defecating, and had less feeling of residue after defecation, so that they have a better defecation pattern. Based on these results, increasing the amount of beverage consumption, especially of water, and drinking greater quantities of beverage before breakfast are ways to reduce constipation.

• Journal of Periodontal and Implant Science
• /
• v.37 no.2
• /
• pp.287-295
• /
• 2007

As a general treatment modality of subgingival tooth defect in aethetic area, implant or crown and bridge therapy after extraction of affected tooth can be used. But as more conservative treatment, crown lengthening can be considered and not to lose periodontal attachment and impair aethetic appearance, surgical extrusion can be considered as a treatment of choice. In this case report, 3 cases of surgical extrusion was represented and appropriate time for initiation of endodontic treatment according to the post-surgical tooth mobility was investigated. In 8 patient who has subgingival tooth defect in aethetic area, intracrevicular incision is performed and flap was reflected with care not to injure interproximal papillae. With forcep or periotome, tooth was luxated and sutured in properely extruded position according to biologic width with or without $180^{\circ}$ rotation. 8 cases show favorable short and long term results. In some cases, surgical extrusion with $180^{\circ}$ rotation can minimized extent of extrusion and semi-rigid fixation without apical bone graft seems to secure good prognosis. In 8 cases, endodontic treatment started about 3 weeks after surgery. This time corresponds with the moment when mobility of extruded tooth became 1 degree and this results concide with other previous reports. If it is done on adequate case selection and surgical technique, surgical extrusion seems to be a good treatment modalilty to replace the implant restoration in aethetic area.

• The Journal of Korean Institute of Communications and Information Sciences
• /
• v.33 no.5A
• /
• pp.509-516
• /
• 2008

The Fast Handover in Hierarchical Mobile IPv6(F-HMIPv6) scheme provides a seamless handover in mobile IP networks effectively. However, there is a problem that the mobile node can lose its connectivity to the previous access router because of a sudden degradation of the link quality during fast handover procedure. Additionally, in many cases, the mobile node does not have enough time to exchange messages during the fast handover procedure, especially in case of movement with high speed during handover. In this paper, we propose a modification to F-HMIPv6 that significantly reduces the time to exchange messages during fast handover procedure and thereby increases the probability which the F-HMIPv6 can perform the fast handover in predictive mode.

• Korean Journal of Exercise Nutrition
• /
• v.25 no.1
• /
• pp.30-34
• /
• 2021

[Purpose] Many studies have observed a high prevalence of erectile dysfunction among individuals performing physical activity in less leisure-time. However, this relationship in patients with type 2 diabetic patients is not well studied. In exposure outcome studies with ordinal outcome variables, investigators often try to make the outcome variable dichotomous and lose information by collapsing categories. Several statistical models have been developed to make full use of all information in ordinal response data, but they have not been widely used in public health research. In this paper, we discuss the application of two statistical models to determine the association of physical inactivity with erectile dysfunction among patients with type 2 diabetes. [Methods] A total of 204 married men aged 20-60 years with a diagnosis of type 2 diabetes at the outpatient unit of the Department of Endocrinology at PSG hospitals during the months of May and June 2019 were studied. We examined the association between physical inactivity and erectile dysfunction using proportional odds ordinal logistic regression models and continuation ratio models. [Results] The proportional odds model revealed that patients with diabetes who perform leisure time physical activity for over 40 minutes per day have reduced odds of erectile dysfunction (odds ratio=0.38) across the severity categories of erectile dysfunction after adjusting for age and duration of diabetes. [Conclusion] The present study suggests that physical inactivity has a negative impact on erectile function. We observed that the simple logistic regression model had only 75% efficiency compared to the proportional odds model used here; hence, more valid estimates were obtained here.

• Journal of Wellbeing Management and Applied Psychology
• /
• v.7 no.2
• /
• pp.49-56
• /
• 2024

Purpose: Construction sites are currently facing a socialization problem as the incidence of thermal disease-related disasters increases due to summer heat waves, exacerbated by factors like the concentration of middle-aged and older workers and global warming. The reason why construction sites are particularly vulnerable to heat waves is that there are many outdoor work, which is the peculiarity of the construction industry, and most of the construction workers are elderly. This study analyzes disaster statistics of workers at construction sites for five years to investigate the occurrence of thermal diseases and analyze factors through disaster cases to provide basic data for future disasters to be reduced. Research design, data, and methodology: According to the Construction Workers' Mutual Aid Association, as of June, more than 60% of the construction workers working in the field were in their 50s and 60s. More than 24% are in their 60s and older. Thermal diseases caused by heat waves occur when exposed to high heat or strong sunlight for a long time, accompanied by headaches and dizziness. The problem is that many elderly people have underlying diseases, so if they lose consciousness, they cannot easily recover and are likely to die. Results: According to industrial accident statistics, 182 people were injured by heat-related diseases in the summer from 2016 to 2021, of which 29 died. In particular, in the construction industry, which has a lot of outdoor work, 87 people were injured and 20 people died. Conclusions: In order to prevent heat diseases caused by outdoor work, it is emphasized that exposure time is controlled, and sufficient rest and hydration are essential. Rest, water, and shade are in line with the three principles.