• Investigative Magnetic Resonance Imaging
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• v.21 no.4
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• pp.199-209
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• 2017

Purpose: Caffeine is the most widely consumed psychostimulant. It is often adopted as a tool to modulate brain activations in fMRI studies. However, its pharmaceutical effect on task-induced deactivation has not been fully examined in fMRI. Therefore, the purpose of this study was to examine the effect of caffeine on both activation and deactivation under sustained attention. Materials and Methods: Task fMRI was acquired from 26 caffeine naive healthy volunteers before and after taking caffeine pill (200 mg). Results: Statistical analysis showed an increase in cognition-load dependent task activation but a decrease in load dependent de-activation after caffeine ingestion. Increase of attention and memory task activation and its load-dependence suggest a beneficial effect of caffeine on the brain even though it has no overt behavior improvement. The reduction of deactivation by caffeine and its load-dependence indicate reduced facilitation from task-negative networks. Conclusion: Caffeine affects brain activity in a load-dependent manner accompanied by a disassociation between task-positive network and task-negative network.

• Journal of the Korean Operations Research and Management Science Society
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• v.33 no.4
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• pp.13-30
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• 2008

We explore the determinants of long-term relationship between the buyer and the supplier to help suppliers develope a strategy to build long-term relationship with their buyers. Based upon an extensive literature review, we propose three droops of independent variables which may affect long-term relationship, including (a) environmental factors (product complexity, product importance, source dependence, price sensitivity), (b) relational factors(trust, commitment, satisfaction, intention of expansion), (c) operational performance(quality, delivery, cost capability, technical knowhow). The buyer's actual period of relationship with its main supplier is used as a dependent variable. Using hierarchical multiple regression analysis, we empirically test hypotheses, analysing a sample of 290 manufacturing firms in the U.S. The statistical results indicate that the buyer's source dependence, price sensitivity and the supplier's commitment play a significant role in establishing long-term relationship between the buyer and the supplier. However, the supplier's cost capability and technical knowhow in operational performance negatively affect long-term relationship in contrast with our hypotheses. Due to this controversial result, we divide the sample group Into dual sourcing and multiple sourcing environments and reconduct regression analysis in a post hoc manner. The findings show that the supplier's cost capability and technical knowhow are negatively associated with the length of relationship only in the multiple sourcing environment. The results may confirm that both parties' opportunistic behavior is more salient in the multiple sourcing environment than in the single sourcing environment.

• The Journal of Society for e-Business Studies
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• v.18 no.1
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• pp.13-31
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• 2013

This paper proposes a new concept of inter-organizational systems (IOS) visibility, considering the key role of IOS in IT-enabled supply chain (SC) cooperation. Further, antecedents and consequences IOS visibility have been studied. Antecedents of IOS visibility are identified from the two conflicting theories of inter-organizational relationships, i.e., RDT(resource dependence theory) and RV(relational view). Investigating SC cooperation from the perspectives of both partners (buyers and suppliers) is important, especially when channel partners depend on each other and when asymmetries in IOS visibility can exist. Hence, this study attempts to accommodate both partners' perspectives in IOS visibility and to look into the consequences of IOS visibility from each participant's perspective.

• Korean Journal of Materials Research
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• v.5 no.6
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• pp.639-643
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• 1995

The temperature dependence of the dark conductivity was studied on undoped hydrogenated amorphous germanium (a-Ge : H) over the range from 297 to 423 K. The pre-exponential factor $\sigma$$\_$0/ and activation energy E$\_$C/-E$\_$F/ are determined by an Arrhenius plot. The Arrhenius plot of the electrical conductivity shows a kink around the kink temperature and then is composed of two exponential functions. The obtained statistical shift ${\gamma}$$\_$F/ was about 8.65${\times}$10$\^$-3/eV/K and the pre-exponential factor $\sigma$$\_$0/ was about 2$\Omega$$\^$-1/cm$\^$-1/. A temperature dependent defect density is numerically calculated from the conductivity data. A change of the defect density is observed in the factor of about two in the range of the experimental temperature.

• Korean Journal of Biological Psychiatry
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• v.6 no.1
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• pp.102-110
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• 1999

Objectives : The alcohol dependence in elderly people has been prevalent because of increase in geriatric population. However, it is difficult to find out alcohol dependence in the aged, because they have less specific clinical features as compared with adult alcoholics. The aims of this study were to screen alcohol dependence among elderly Koreans and to know the clinical characteristics of Korean delerly alcoholics. Methods : The questionnaires translated into Korean such as Michigan Alcoholism Screening Test(MAST-K), the Brief MAST and the MAST-Geriatirc Version (MAST-KG) were used to screen alcohol dependence in the elderly alcoholic inpatients aged over 60(N=43), adult alcoholic inpatients within 20-59 Yrs of age(N=60), which were compared with age matched normal healthy aged(N=18) or adult controls(N=45). The demographic data such as sex, age, education, occupation, socioeconomic status, marital status, numbers of children, dwelling and religion as well as alcohol history such as duration of alcohol drinking, onset age, family history, impulsivity, somatic illness and motivation were also obtained to identify characteristic features of Korean aged alcoholics by structured interviews. Results : 1) The aged alcoholics had the charateristic features of more in males, lower age, low education levels, more in blue-collar workers, lower socioeconomic class, more in single, few babies, more living alone, having no religion without statistical significance. 2) The onset age of alcohol dependence was significantly higher in the aged alcoholics($45.3{\pm}13.6Yrs$) than in the adult alcoholics($27.7{\pm}8.7Yrs$)(p<0.0001). The duration of problematic alcohol drinking was significantly longer in the aged alcoholics($22.0{\pm}15.1Yrs$) than in adult alcoholics($14.2{\pm}8.4Yrs$)(p<0.01). Otherwise, there were no significant difference between aged and adult alcoholics in the family history, imulsivity, somatic illness and motivation. 3) The mean score of the MAST-K was significantly higher in the aged alcoholics($20.6{\pm}5.4$) than in the normal aged($6.7{\pm}4.4$)(p<0.0001), which was significantly lower than in the adult alcoholics($26.2{\pm}8.0$) and in normal adult controls($9.5{\pm}3.2$)(p<0.05). The mean score of the Brief MAST was significantly lower in the aged alcoholics($9.3{\pm}3.5$) than in the adult alcoholics($14.5{\pm}6.6$)(p<0.0001). The mean score of the MAST-KG was significantly higher in the aged alcoholics($10.6{\pm}3.5$) than in the normal aged($4.8{\pm}4.3$)(p<0.0001). The former was significantly lower than in the adult alcoholics($12.9{\pm}4.3$)(p<0.005), and the mean score was $4.5{\pm}2.8$ in normal adult controls. 4) The items which showed statistically significant differences between aged alcoholics and normal aged controls could be found in 10 items of the MAST-K(items 2, 3, 4, 5, 11, 14, 17, 21, 22 and 23), 2 items of the Brief MAST(items 2 and 9), and 7 items of the MAST-KG(items 6, 13, 18, 19, 22, 23 and 24)(p<0.01). Conclusions : The scores of the MAST-K, the Brief MAST and the MAST-KG were significantly lower in the aged alcoholics than those in the adult alcoholics (p<0.05). The statistically significant differences between aged alcoholics and normal aged controls could be found in 10 items of the MAST-K, 2 items of the Brief MAST and 7 items of the MAST-KG. Therefore, a briefer rating scales around 10 items are needed to screen alcohol dependence among Korean elderly people.

• Spatial Information Research
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• v.20 no.1
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• pp.81-90
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• 2012

When analyzing geographical phenomena, two properties need to be considered. One is the spatial dependence structure and the other is a variation or an uncertainty inhibited in a geographic space. Two problems are encountered due to the properties. Firstly, spatial dependence structure, which is conceptualized as spatial autocorrelation, generates heterogeneous geographic landscape in a spatial process. Secondly, generic statistics, although suitable for dealing with stochastic uncertainty, tacitly ignores location information im plicit in spatial data. GIS is a versatile tool for manipulating locational information, while spatial statistics are suitable for investigating spatial uncertainty. Therefore, integrating spatial statistics to GIS is considered as a plausible strategy for appropriately understanding geographic phenomena of interest. Geographic hot-spot analysis is a key tool for identifying abnormal locations in many domains (e.g., criminology, epidemiology, etc.) and is one of the most prominent applications by utilizing the integration strategy. The article aims at reviewing spatial statistical perspective for analyzing spatial processes in the framework of GIS by carrying out empirical analysis. Illustrated is the analysis procedure of using spatial scan statistic for detecting clusters in the framework of GIS. The empirical analysis targets for identifying spatial clusters of breast cancer incidents in Erie and Niagara counties, New York.

• Research in Community and Public Health Nursing
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• v.10 no.2
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• pp.372-386
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• 1999

The purpose of this study was to explore the degree of stress in caregivers caring for CVA patients and the level of daily living performance of CVA patients. The subjects for the study were caregivers of 112 CVA patients who enter a hospital or out-patient-department (OPD) at two Oriental medical hospital in Jeonbuk province. The survey instruments used in this study were Kang's ADL check list for daily living performance of patients and Choi's 4 sore scale for stress of caregivers. The survey was conducted from July 4th to August 30th in 1999. The survey results were analyzed with the Statistical Package for Social Science(SPSS) program and can be summarized as follows: 1. The level of daily living performance for the CVA patients was: 1) complete dependence (M=14.9, 13.1%), 2) complete independence (M=23.6, 20.9%), 3) incomplete independence (M=23.9, 21.0%), 4) incomplete dependence (M=26.6, 25%), 5) dependence and independence (M=23.0, 20.0%). The items for with there was a high level daily living performance were: 1) drinking (M=3.62), 2) eating(M=3.25). 3) position returning (M=3.18) : and the items for which there was a low level of daily living performance were: 1) ascending and descending stairs (M=2.08), 2) walking (M=2.47), 3) dressing and undressing trousers (M=2.55). 2. Degree of caregiver stress was: Mean=2.39 at 40 score. The items for which was a high level caregiver stress were: 1) medical fee (M=3.25), 2) being handicapped or recurrence (M=3.02) : and the items for which there was a low level of caregiver stress were: 1) discontinuity of patient's treatment (M = 1.98). 2) change of home atmosphere caused by patient's disease (M = 1.98), 3) desire of patient's knowing about disease (M= 1.99). 3. There was statistically significant difference in the degree of caregiver stress according to the following caregiver's demographic characteristics: education level (F=3.52, P=0.03). change of caregiver (F=5.41. P=0.02). 4. There was a statistically signifiant difference in the level of daily living performance according to the CVA patients demographic characteristics: patient's paralytic status (F=4.48, P=0.01), duration of disease (t=2.76, P=0.03). 5. There was significant difference in degree of caregiver stress according to the CVA patient's demographic characteristics: CVA status (F=4.75, P=0.01). 6. There was statistically significant difference in the degree of caregiver stress according to the level of daily living performance in CVA patients(r=-0.482, P<0.00).

• Korea Journal of Hospital Management
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• v.3 no.1
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• pp.62-82
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• 1998

The purpose of this study is to assess the cause and level of conflict arising within and between departments among administration office workers who work in a recently established tertiary hospitals of a major cooperation or related non-profit cooperation: The study also aimed to find methods for resolution of such conflicts by comparing with other existing university hospitals. The subject population included 299 business administration office workers randomly selected from two cooperate related tertiary hospitals of less than 3 years in its existence and two university hospitals over 700 beds in Seoul and Kyong In area. Data were collected through a survey questionnaire. To define related factors for the level of conflict among departments in each hospitals multivariate regression analysis was conducted. Independent factors were characteristics of subjects, conflicting factors within and between the departments. The results are as follows: 1. Those in the 30-39 rears of age group demonstrated significantly higher level of conflict between departments. Those working in the new hospitals, who were older and had long-term tenure, and those with short-term job experience at current working hospital had higher level of conflict between the departments with statistical significance. 2. Concerning the involvement of conflicting factors and the level of conflict in the administration there was statistically significant positive correlation between reliability and job-related intra- and interdepartmental level of conflict in existing hospitals. There was a significant positive correlation between intradepartmental conflicting factors of mutual dependence, difference in goal/orientation and intra- and interdepartmental level of conflict. 3. In multivariate regression analysis, women more than men, and those who had worked for many years in hospitals had statistically significant influence on factors involved in interdepartmental level of conflict, explaining 51.0% of the model. 4. In existing hospitals, gender was a significant factor with women showing a higher level of interdepartmental conflict compared to men. Among the interdepartmental factors, mutual dependence had statistically significant influence and showed a positive relationship with interdepartmental level of conflict. In the new hospitals, job position was a significant factor which showed that those in high position such as section chief or above, compared to those in managerial or general position had higher level of conflict. Among the interdepartmental characteristics, factors of mutual dependence and goal/orientation had statistically significant influence and showed a positive relationship with interdepartmental level of conflict. In the new hospital setting efforts to reduce conflict in areas among workers with high position, old age, and long tenure and those in Purchasing, Material and Computer Department should be made and prudent management and planning for improved manpower and increased budget or efficient allocation and clear definition of job description are necessary to adequately assess and make improved efforts for rapid stabilization of the premature hospital system from its inception, In the existing hospitals a lack of conflict within and between departments may give rise to stagnation or inefficiency of the organization. Future study are needed with respect to the relationship between interdepartmental level of conflict and the effectiveness of the hospital organization for improved resolution of conflict in the organization and hospital management.

• Journal of muscle and joint health
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• v.7 no.2
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• pp.241-257
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• 2000

Rheumatoid arthritis as one of the chronic illness requiring management in long period of time puts great burden to patients, their family and society. For patients with chronic illnesses, providing a social support is important and the most important source comes from spouses. Therefore we assessed burden of husbands of female rheumatoid arthritic patients and also found out the factors affecting burden. The sample of study was 107 female rheumatoid arthritic patients and their spouses. The tool of assessing spouses' burden was the revised version of subjective and objective parameters developed by Montgomery et al.(1985). The results are as follows: 1. General characteristics of patients and spouses: The mean age of the patients was 48 years. Educational level of patients was high school 41.1%. The mean age of the spouses was 51years. Educational level of spouses was mostly high school(40.2%) and college(29.9%) graduate. The mean marital period was 23.4years. Average income per month was 1,609,000 won. The average duration since diagnosis was 9.4years. As a therapy, 67.3% chose standard drug therapy. Average rating of discomfort by patient was 3.05(range 1-5) and that of severity was 3.48 and that of dependency was 2.58. The husband's rating of their spouses disease severity was 3.68. 2. Husbands' burden: The average burden in subjective items was 21.61(range 6-36) and objective items was 35.24(range 10-60). The average of total burden was 56.59(range 16-96). 3. Husband's total burden correlated with patient's age, educational level of patients, therapy method, patient's level of discomfort, patient's severity, patient's level of dependence, husband's recognition of level of severity in statistical level. Husband's objective burden correlated with patient's age, educational level of patient, patient's level of discomfort, husband's recognition of level of severity. Husband's subjective burden correlated with patient's age, educational level of patients, therapy method, patient's severity, patient's level of dependence, husband's recognition of level of severity. 4. Linear correlation analysis on burden: The husbands' total burden is explained in 37 7% by husband's recognition of level of severity and husband's age. The husbands' objective burden is explained in 31.2% by patient's level of dependence, husband's age, husband's recognition of level of severity. The husbands' subjective burden is explained in 26.7% by husband's recognition of level of severity and patient's age. In conclusion, husbands' level of burden is affected by many factors and therefore nursing strategy for relieving burden of middle aged husbands should be individualized taking these factors into consideration.

• KIEE International Transactions on Electrophysics and Applications
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• v.11C no.4
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• pp.120-126
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• 2001

For the past five years, Inha University has been observing the electric fields produced by cloud-to-ground return strokes. This paper presents the summary of most recent results. Statistics on the zero-to-peak rise time, the zero-to-zero crossing time and the amplitude ratio of the second peak in the opposite polarity to the first peak were examined. The radiation electric fields produced by distant cloud-to-ground return strokes were substantially same pattern. The first return stroke field starts with a slowly increasing front and rises abruptly to peak. The rising portions of the electric fields produced by cloud-to-ground return strokes last 1 $mutextrm{s}$ to a few $mutextrm{s}$. The mean values of the zero-to-peak rise times of electric fields were 5.72 $mutextrm{s}$ and 4.12 $mutextrm{s}$ for the positive and the negative cloud-to-ground return strokes, respectively. The mean of the zero-to-zero crossing time for the positive return strokes was 29.48 $mutextrm{s}$ compared with 38.54 $mutextrm{s}$ for the negative return strokes. The depths of the dip after the peak of return stroke electric fields also have the dependence on the polarity of cloud-to-ground return stroke, and the mean values for the positive and negative cloud-to-ground return strokes were 33.55 and 28.19%, respectively.