• Journal of Korean Neurosurgical Society
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• v.29 no.4
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• pp.461-470
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• 2000

Objective : Many investigators have demonstrated the protective effects of hypothermia following traumatic brain injury(TBI) in both animals and humans. It has long been recognized that mild to moderate hypothermia improves neurologic outcomes as well as reduces histologic and biochemical sequelae after TBI. In this study, two immunohistochemical staining using terminal deoxynucleotidyl-transferase-mediated biotin dUTP nick end labeling(TUNEL), staining of apoptosis, and ${\beta}$-amyloid precursor protein(${\beta}$-APP), a marker of axonal injury, were done and the authors evaluated the protective effects of hypothermia on axonal and neuronal injury after TBI in rats. Material and Method : The animals were prepared for the delivery of impact-acceleration brain injury as described by Marmarou and colleagues. TBI is achieved by allowing of a weight drop of 450gm, 1 m height to fall onto a metallic disc fixed on the intact skull of the rats. Fourty Sprague-Dawley rats weighing 400 to 450g were subjected to experimental TBI induced by an impact-acceleration device. Twenty rats were subjected to hypothermia after injury, with their rectal temperatures maintained at $32^{\circ}C$ for 1 hour. After this 1-hour period of hypothermia, rewarming to normothermic levels was accomplished over 30-minute period. Following 12 hours, 24 hours, 1 week and 2 weeks later the animals were killed and semiserial sagittal sections of the brain were reacted for visualization of the apoptosis and ${\beta}$-APP. Results : The density of ${\beta}$-APP marked damaged axons within the corticospinal tract at the pontomedullary junction and apoptotic cells at the contused cerebral cortex were calculated for each animal. In comparison with the untreated controls, a significant reduction in ${\beta}$-APP marked damaged axonal density and apoptotic cells were found in all hypothermic animals(p<0.05). Conclusion : This study shows that the posttraumatic hypothermia result in substantial protection in TBI, at least in terms of the injured axons and neurons.

• The Korean Journal of Applied Statistics
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• v.28 no.5
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• pp.977-990
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• 2015

Food delivery services are well developed in the Republic of Korea, The increase of one person households and the success of app applications influence delivery services these days. We consider a prediction model for the food delivery service based on weather and dates to predict the number of food delivery services in 2014 using various data mining techniques. We use linear regression, random forest, gradient boosting, support vector machines, neural networks, and logistic regression to find the best prediction model. There are four categories of food delivery services and we consider two methods. For the first method, we estimate the total number of delivery services and the posterior probabilities of each delivery service. For the second method, we use different models for each category and combine them to estimate the total number of delivery services. The neural network and linear regression model perform best in the first method, this is followed by the neural network which is the best for the second method. The result shows that we can estimate the number of deliveries accurately based on dates and weather information.

• IE interfaces
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• v.17 no.1
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• pp.71-77
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• 2004

At the present time, container transportation plays a key role in the international logistics and the efforts to increase the productivity of container logistics become essential for Korean trucking companies to survive in the domestic as well as global competition. This study suggests an approach for determining fleet size for container road transportation with dynamic demand. Usually the vehicles operated by the transportation trucking companies in Korea can be classified into three types depending on the ways how their expenses occur; company-owned truck, mandated truck which is owned by outsider who entrust the company with its operation, and rented vehicle (outsourcing). Annually the trucking companies should decide how many company-owned and mandated trucks will be operated considering vehicle types and the transportation demands. With the forecasted monthly data for the volume of containers to be transported a year, a heuristic algorithm using tabu search is developed to determine the number of company-owned trucks, mandated trucks, and rented trucks in order to minimize the expected annual operating cost. The idea of the algorithm is based on both the aggregate production planning (APP) and the pickup-and-delivery problem (PDP). Finally the algorithm is tested for the problem how the trucking company determines the fleet size for transporting containers.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.23 no.6
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• pp.27-32
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• 2023

Location sharing through apps is increasing, such as finding a friend's location or sharing delivery status on the Internet. However, location information is important personal information, and in some cases can be misused for crimes, and so encryption of location information is essential when developing such apps. This paper develops an app that encrypts and shares location information between friends for purposes such as finding friends and deciding meeting locations. To improve encryption performance, the symmetric key was encrypted and transmitted using an asymmetric key, and for location sharing, only the symmetric key was used to encrypt it. The proposed app was developed on iOS, and performance measurements showed that encryption of location information was at least 5,000 times faster when using a symmetric key than when using an asymmetric key.

• Journal of Korean Society for Quality Management
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• v.52 no.1
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• pp.23-42
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• 2024

Purpose: This study aims to investigate the impact of two types of information quality, which are platform-oriented information quality and customer-oriented information quality, on customers' decision-making processes in the Online to offline (O2O) platform environment. Grounded in the product brokering efficiency model, which encompasses screening cost, evaluation cost, and decision quality, a model framework was developed. Furthermore, this study explores how these decision-making processes affect customer loyalty. Methods: Given that food delivery apps are the most widely used O2O service in Korea, this study targeted users of these apps for data analysis. We conducted hypothesis testing through a purposive sampling methodology focusing on food delivery app users. A Partial Least Squares Structural Equation Modeling analysis was conducted to analyze the data. The data collection occurred via an online survey from October to December 2021, with a total of 212 respondents participating. Results: The results of this study revealed the significant role of information quality in helping customers' decision processes while using food delivery apps. Specifically, it was found that platform-oriented information positively influences decision quality, while customer-oriented information significantly affects both the reduction of evaluation cost and the enhancement of decision quality. Additionally, the study indicated that lower evaluation costs and higher decision quality lead to increased platform loyalty. However, a reduction in screening cost did not have a significant impact on platform loyalty. Conclusion: While previous studies have overlooked the existence of two sides, service provider and user, in a platform, this research holds significance in its analysis of how information quality impacts loyalty by utilizing the two kinds of information quality. Practitioners can enhance customer loyalty to the platform by enriching customer-oriented information, thereby reducing customers' evaluation costs and encouraging more loyal usage of the platform.

• The Journal of the Korea Contents Association
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• v.19 no.10
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• pp.581-592
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• 2019

This study investigates the factors that stimulate or suppress the use of food delivery applications. As potential antecedent factors, the present research examined the review diagnosticity, descriptive norms, and multidimensional risk perception. Based on this, users' data were collected from major metropolitan cities where the food delivery application business is most active. The results of structural equation modeling confirmed that users' approach to food delivery apps becomes more favorable when the review diagnosticity and descriptive norms were improved and when the perceived multidimensional risk expected to be associated with app use is mitigated. Additionally, we found that the positive influence of these attitudes on the actual intention to accept delivery applications became weaker at higher levels of perceived risk. These empirical results may contribute to the formation of strategic and systematic guidelines for promoting the expansion of the recently emerging O2O service platform across diverse sectors. Namely, the significance of this study lies in that it has raised awareness regarding the strategic considerations that such new O2O service providers should take into account for their market positions, in addition to discovering factors that could aid the prompt expansion of the applications' user base.

• Journal of Service Research and Studies
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• v.13 no.2
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• pp.1-23
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• 2023

In this study, we try to discover some success factors, for the entire value chain of the O2O food delivery industry in China, from ordering to delivery. We study the influence of three aspects of the value chain, namely, (1) the mobile platform, (2) the restaurant and food and (3) the delivery service, on the perceived value and repurchase intention of customers. Using structural equation modeling, we develop a structural research model with seven sets of hypotheses relating various independent variable constructs (platform, restaurant, and delivery) and dependent constructs (perceived value and repurchase intention). We find that usefulness of mobile app, the food condition and the availability of offline restaurants were significant antecedents for perceived value and repurchase intention. In addition, fair pricing was a significant antecedent for repurchase intention.

• Annual Conference of KIPS
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• 2022.11a
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• pp.290-291
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• 2022

점심이나 저녁을 위한 간단한 음식을 주문하고자 할 때 배달료가 비싸서 망설이거나 포기하는 경우가 많다. 이 발표에서는 가까운 지인이 아니더라도 배달 장소가 동일한 어느 누구와도 함께 주문함으로써 배달비를 절감할 수 있는 앱을 설계하고 구현한다. 개발된 앱은 여러 음식점을 등록하여 각 음식점에서 판매하는 다양한 메뉴 주문과 배달지 선택 기능을 제공한다.

• Journal of Pharmaceutical Investigation
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• v.25 no.4
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• pp.353-363
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• 1995

The purpose of this study was to investigate the intestinal and nasal absorption enhancement of cefotaxime (CTX) by ion-pairing with counterions and to design an effective oral and intranasal drug delivery system for antibiotics. Counterions for absorption promotion were cationic surfactants [cetylpyridinium chloride (CP), cetrimide (CT) and benzalkonium chloride (BA)]. In the presence of counterions, the apparent partition coefficient of cefotaxime was increased depending on the molar concentration of the counterions. Anion interference was observed for ion-pairing of cefotaxime with counterions because of the counterbalance between an anion and counterions. The present study employed the in situ simultaneous nasal and intestinal perfusion technique in rats. The apparent permeabilities $(P_{app})$ of cefotaxime were $1.43{\pm}0.04{\times}10^{-5}\;cm/sec(mean{\pm}S.E)$ in the nasal cavity and 0 in the jejunum, respectively, which indicated that the intrinsic absorptivity of cefotaxime was greater in the nasal cavity than in the jejunum. When ionupairing formers were used, the decreasing order of apparent cefotaxime permeability $(P_{app},\;10^{-5}\;cm/sec)$, corrected for surface area of absorption, was as followings: $BA\;(7.50{\pm}0.36)\;>\;CT\;(4.92{\pm}0.24)\;>\;CP\;(3.01{\pm}0.17)$ in the jejunum and $BA\;(22.31{\pm}1.36)\;>\;CP\;(18.24{\pm}0.81)\;>\;CT \;(16.22{\pm}1.87)$ in the nasal cavity. The increase in permeability of cefotaxime was about 13-fold in the rat nasal cavity and was marked in the rat jejunum for ion-pairing with counterions as compared to those without ion-pairing. The damages of jejunal and nasal mucosal membrane by counterions were observed within approximately 2hrs after removal of ion-pair of cefotaxime with counterions from the nasal cavity and jejunum. These results suggest that CP can be used as an ion-pairing former in the jejunum and CP and CT can be used as ion-pairing formers in the nasal cavity for cefotaxime, as well as for poorly absorbed drugs with a negative charge due to ionization.

• Journal of Chest Surgery
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• v.55 no.2
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• pp.108-117
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• 2022

Background: The efficacy of telemedicine among cancer survivors is uncertain. The Smart After-Care Program (SAP), which is an interactive, smartphone-based remote health monitoring system, was developed to help patients manage their health after leaving the hospital. This study was designed to evaluate the efficacy of our remote health care program for lung cancer patients. Methods: We enrolled 50 patients with lung cancer. Self-monitoring devices were supplied to all patients, who were instructed to enter their daily vital signs and subjective symptoms to the Smart After-Care app. The app also provided information about rehabilitation exercises and a healthy diet for lung cancer patients. All patients received health counseling via telephone once a week and visited an outpatient clinic during weeks 6 and 12 to assess satisfaction with the SAP and changes in quality of life and physical performance. Results: Overall satisfaction with the SAP was very high (very good, 61.9%; good, 26.2%). In the multivariate analysis to identify factors affecting satisfaction, the distance between the patient's residence and the hospital was the only significant independent factor (p=0.013). Quality of life improved along all functional scales (p<0.05). Muscle strength significantly improved in the lower limbs (p=0.012). Two-minute walk distance also significantly improved (p=0.028). Conclusion: This study demonstrated that the SAP was acceptable for and supportive of patients with reduced pulmonary function after lung cancer treatment. The SAP was found to be particularly useful for patients living far from the hospital.