• Journal of Intelligence and Information Systems
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• v.21 no.1
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• pp.119-142
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• 2015

With the explosive growth in the volume of information, Internet users are experiencing considerable difficulties in obtaining necessary information online. Against this backdrop, ever-greater importance is being placed on a recommender system that provides information catered to user preferences and tastes in an attempt to address issues associated with information overload. To this end, a number of techniques have been proposed, including content-based filtering (CBF), demographic filtering (DF) and collaborative filtering (CF). Among them, CBF and DF require external information and thus cannot be applied to a variety of domains. CF, on the other hand, is widely used since it is relatively free from the domain constraint. The CF technique is broadly classified into memory-based CF, model-based CF and hybrid CF. Model-based CF addresses the drawbacks of CF by considering the Bayesian model, clustering model or dependency network model. This filtering technique not only improves the sparsity and scalability issues but also boosts predictive performance. However, it involves expensive model-building and results in a tradeoff between performance and scalability. Such tradeoff is attributed to reduced coverage, which is a type of sparsity issues. In addition, expensive model-building may lead to performance instability since changes in the domain environment cannot be immediately incorporated into the model due to high costs involved. Cumulative changes in the domain environment that have failed to be reflected eventually undermine system performance. This study incorporates the Markov model of transition probabilities and the concept of fuzzy clustering with CBCF to propose predictive clustering-based CF (PCCF) that solves the issues of reduced coverage and of unstable performance. The method improves performance instability by tracking the changes in user preferences and bridging the gap between the static model and dynamic users. Furthermore, the issue of reduced coverage also improves by expanding the coverage based on transition probabilities and clustering probabilities. The proposed method consists of four processes. First, user preferences are normalized in preference clustering. Second, changes in user preferences are detected from review score entries during preference transition detection. Third, user propensities are normalized using patterns of changes (propensities) in user preferences in propensity clustering. Lastly, the preference prediction model is developed to predict user preferences for items during preference prediction. The proposed method has been validated by testing the robustness of performance instability and scalability-performance tradeoff. The initial test compared and analyzed the performance of individual recommender systems each enabled by IBCF, CBCF, ICFEC and PCCF under an environment where data sparsity had been minimized. The following test adjusted the optimal number of clusters in CBCF, ICFEC and PCCF for a comparative analysis of subsequent changes in the system performance. The test results revealed that the suggested method produced insignificant improvement in performance in comparison with the existing techniques. In addition, it failed to achieve significant improvement in the standard deviation that indicates the degree of data fluctuation. Notwithstanding, it resulted in marked improvement over the existing techniques in terms of range that indicates the level of performance fluctuation. The level of performance fluctuation before and after the model generation improved by 51.31% in the initial test. Then in the following test, there has been 36.05% improvement in the level of performance fluctuation driven by the changes in the number of clusters. This signifies that the proposed method, despite the slight performance improvement, clearly offers better performance stability compared to the existing techniques. Further research on this study will be directed toward enhancing the recommendation performance that failed to demonstrate significant improvement over the existing techniques. The future research will consider the introduction of a high-dimensional parameter-free clustering algorithm or deep learning-based model in order to improve performance in recommendations.

• The Journal of Korean Academy of Sensory Integration
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• v.6 no.1
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• pp.47-62
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• 2008

Introduction : Sensory Integration(SI) theory, science it is developed by an occupational therapist A. Jean Ayres, is the one of the most popular frames of reference used in occupational therapy(OT) intervention. It has been proved as a scientific theory especially in neuroscience discipline through abundant research and practice. Occupational therapists apply the SI therapy with strong clinical reasoning to improve adaptive behaviors of their clients and try to link the adaptive behaviors with occupational performance in the clients' everyday life. One of the manners regarding clinical reasoning is Top-down approach. In occupational therapy discipline, Top-down approach is well-reflected within two evaluation tools; Canadian Occupational Performance Measure(COPM) and Assessment of Motor and Process Skills(AMPS) and two models of practice; Canadian Model of Occupational Performance(CMOP) and Occupational therapy intervention process model(OTIPM). Objective : The purpose of this paper demonstrates how SI therapy can be employed within OTIPM and how the OT process (evaluation-intervention-outcome) can be structuralized based on the Top-down approach. This single-case study recognizes the impact of a SI therapy for a male adolescent on his occupational performance. Intervention Examined : "P" was 16 years old male adolescent with no diagnosis and junior of the high school when he was referred. P was always with mouth opened, showed difficulties in gathering things need to be prepared and managing and paying money for shopping, and his colleges dislike getting close to him because he can't was his body well. AMPS was administrated in initial evaluation and reevaluation of P's occupation performance, Bruininks-Oserestky Test of Motor Proficiency-2(BOT-2) was carried out to assess motor functions and perception skills related in sensory integration, and occupational therapist performed clinical observation in order to complement the evaluation quantitatively and quantitatively. Based on the evaluation, it is concluded that the SI therapy is primary means to improve P's occupational performance, and three therapeutic approaches were constructed; restorative, acquired and compensatory approach. P showed improved motor and process skills in occupational performance after undergone the occupational therapy. Conclusions : The sensory integration therapy was practical enough to build the bridge between the occupational performance(Top) and the underlying component problems (Bottom). The OTIPM was helpful to identify meaningful occupation for P and P's family within P's contexts, and the AMPS was valuable to analyze and clarify the cause of difficulties in the chosen occupational performance.

• The Korean Journal of Elementary Counseling
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• v.5 no.1
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• pp.227-253
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• 2006

It seems common for students living at a small county and islands to experience psychological conflicts and be unaccustomed in the peer society because they are not familiar with peer interaction and social skills. This is a case study of L (hereinafter called L) who was grown up in the sheltered school at a small county. L was psychologically disturbed because he couldn't get along well in the transferred school. It is the reason why he had lived in the sheltered school at a small county, so he had not enough exposure to interact with peer and social skills. Sometimes he was obstinate irrationally and when he had trouble with friends, he threw something out or went out of school and tricked juniors dangerously. The fact of disperse with families, parent's indifference, and hate of older brother made L to have ill feeling against family. He had low motivation and low self confident in learning because of short attention time and accumulated poor learning progress. In this study, he was evaluated at various area, such as, intelligent, affective, personal and inter-personal, before counselling. To evaluated the effect of the counselling, K-WISC-III, KPRC, sentence filling test, social adaptation ability test, etc, were administered right after the counselling was over and 8 weeks later. For specific information gathering and analysing, observation diary and deepen counselling were accomplished by homeroom teacher, his mother, and his peers. To correct his problematic behaviors, 13 counseling sessions were accomplished for 6 months and those counselling sessions were recorded and analysed definitely. Followings are the result of this case study. First, he was recovered from the anxiety of inter-personal interaction and he started to interact with peers. The result of sac scale score of KPRC profile was lower than before as much as average student after counseling and 8 weeks later. This reveals that the distress against interpersonal relation have settled. Especially, through the result of sentence filing test, he seemed to feel attachment to peers and be positive, active in the relation of peer. For instance, he was active in the open class lesson and interacted well with peers. It could be said that he overcame the psychological distress comparing with previous time. Second, he could apologize to his peer and juniors for his fault. His attitude were well shown in the letter from an old friend at the sheltered school, average KPRC profiling score comparing with previous counseling time, and remarkable decrease of attack scale score of teacher and peer. Third, his view toward family turn out positive. He recognized his situation that he lived apart from family and even worried about his parent's financial difficulty. Through solving the confliction with his older brother, he could acquire the feeling of family reunion. Fourth, his learning motivation and self-confidence were increased. He confirmed his future positively and he might be judged more attentive because his intelligence index was higher than before as much as average student. With the main goal of this study, verification for effectiveness of counseling. understanding and helping problematic students such as L who lives at a small county and island through investigation of their real situation and problems with the method of counseling and socio-cultural analysis is worthwhile. Identification of ideal relationship with peer is related with positive self-conception, harmonic social adaptation and development of child. It is time to investigate easy adaptive in classroom and well-organised program to acquire general social skills for sheltered school students at a small county and islands.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.15 no.6
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• pp.90-101
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• 2016

This study was initiated to develop an algorithm for traffic condition adaptive optimal traffic signal control for isolated intersections based on the vehicle trajectory data. The algorithm determines the optimal cycle length, phase lengths, phase sequences using the data collected under V2X communication environment every second. In addition, the algorithm utilizes a traditional feature of the actuated signal control, gap-out, using traditional detector systems to consider the mixture of normal vehicles and vehicles equipped with the V2X communication function. The performance of the algorithm was compared with that of the fixed signal timing plan which was optimized with Synchro under a microscopic traffic simulation-based test bed. As a result, the overall performance, including average delay, average stop delay, the number of stops, and average speed, are improved apparently. In addition, the amount of improvement get bigger as the traffic volume in the intersection as well as the number of vehicles equipped with the V2X communication function increase.

• Korean Journal of Childcare and Education
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• v.11 no.4
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• pp.147-166
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• 2015

The purpose of this study was to investigate the effects of maternal psychological control and the disparity between children's temperament and mothers' demand level on children's externalizing and internalizing behavior problems. The participants of this study were 221 children aged 4 to 5 and their mothers from three kindergartens located in Busan and Gyeongsangnam-do. To measure children's behavior problems, the Preschool and Kindergarten Behavior Scales were used. Maternal psychological control was assessed by the Psychological Control Scale-Youth Self-Report. The Revised Dimension of Temperament Survey and DOTS-R: ethnotheory was used, to measure the disparity between children's temperament and mothers' demand level. The data were analyzed by means of descriptive statistics, t-test and hierarchical regression analysis. The results of this study were as follows. First, both for boys and girls, the disparity between children's activity temperament and mothers' demand level had a negative effect on externalizing behavior problems. However, maternal psychological control had no significant effect on externalizing behavior problems both for boys and girls. Second, for boys, the high level of maternal psychological control and the disparity between children's adaptive temperament and mothers' demand level had a negative effect on internalizing behavior problems. However, for girls, such effects were not significant.

• Journal of the Institute of Electronics Engineers of Korea SD
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• v.38 no.8
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• pp.62-71
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• 2001

This paper presents a design of the real-time digital image enhancement preprocessor for CMOS image sensor. CMOS image sensor offers various advantages while it provides lower-quality images than CCD does. In order to compensate for the physical limitation of CMOS sensor, the spatially adaptive contrast enhancement algorithm was incorporated into the preprocessor with color interpolation, gamma correction, and automatic exposure control. The efficient hardware architecture for the preprocessor is proposed and was simulated in VHDL. It is composed of about 19K logic gates, which is suitable for low-cost one-chip PC camera. The test system was implemented on Altera Flex EPF10KGC503-3 FPGA chip in real-time mode, and performed successfully.

• The Journal of Internal Korean Medicine
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• v.27 no.1
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• pp.276-287
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• 2006

Background & Objective : The herbal medicine Sojukgunbihwan granule has been used for the treatment of functional dyspepsia, generally categorized as a gastric dysmotility disease. However, its mechanisms are not yet well known. Therefore, the effects of Sojukgunbihwan granules on gastric motility in rats was investigated. Methods : The myoelectrical activity of the gastric smooth muscle was recorded by a bipolar electrode placed at the gastric antrum of rats. The contractile waves were measured for 30 minutes before and after intragastric administration of each solution(normal saline, Pyungwisan 40mg/kg, Sojukgunbihwan granules 60mg/kg) and expressed as the motility index. Gastric emptying was measured by the number of glass beads expelled from the stomach(containing one hundred 1mm glass beads) within an hour after glass beads and test drugs(normal saline, Pyungwisan 40mg/kg, Pyungwisan 120mg/kg, Sojukgunbihwan granules 60mg/kg, Sojukgunbihwan granules 180mg/kg) were administered. In another series of experiments to evaluate the mechanisms of Sojukgunbihwan granules under delayed conditions, the rats were treated with atropine sulfate(1 mg/kg, s.c.), cisplatin(10mg/kg, i.p.), and NAME($N^G$-nitro-L-arginine methyl ester, 75mg/kg, s.c.) respectively. Results : Intragastric administration of Sojukgunbihwan granules increased the myoelectrical activity significantly, gastric motility index rose 25%, and gastric emptying of glass beads was significantly enhanced over a period of 60minutes. Under the delayed gastric emptying induced by atropine sulfate, cisplatin, and NAME, Sojukgunbihwan granules aggravated gastric emptying in the atropine sulfate($5.71{\pm}3.45\;vs\;3.71{\pm}4.42$) and cisplatin($13.86{\pm}3.53\;vs\;5.14{\pm}5.05$, p<0.01) treated groups, but enhanced gastric emptying in the NAME treated group($5.00{\pm}3.21\;vs\;11.71{\pm}5.65$, p<0.05). Conclusions : Results suggest that Sojukgunbihwan granules stimulate gastric motility through cholinergic and 5-hydroxytryptamine 3 receptors. Results are indicative of Sojukgunbihwan as an especially effective remedy in dysmotility-like functional dyspepsia with impaired reservoir functions such as gastric adaptive relaxation.

• Journal of Korean Society of Transportation
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• v.23 no.7 s.85
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• pp.43-52
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• 2005

Signal timing transition has recently been highlighted with Adaptive Traffic Control Systems (ATCS) providing advanced traffic signal operation including real-time grouping of coordinated intersections. Signal timing transition occurs when such signal timings as cycles and offsets are changed at coordinated intersections. Setting a proper length of signal timing transition has become in interest for real-time coordination. This paper presents a study verifying the effects of different lengths of signal timing transition. Four different transition lengths were tested and compared in simulation environment. They include a single, double, treble, quadruple cycle length transitions. The number of cycles represents the ones used (interpolation) for transition. Signal timings were controlled to be adjusted uniformly and discretely during a transition period. Transition times considered in the test are within ranges of ${\pm}20$ percents of cycle lengths. It was found from the study that a single cycle transition performs better than or at least equal to the ones from the other with fifteen different operational conditions, which are developed based on a hypothetical arterial. It was suggested that a single cycle length transition be beneficial when amount of transition is within ${\pm}20$ percents of cycle lengths.

• Journal of Biomedical Engineering Research
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• v.38 no.4
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• pp.143-152
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• 2017

The main purpose of this research was to examine the EMG characteristics of driver's upper limb and driving performance for operating accelerator and brake pedal by using four types of left hand control devices(Push/Pull, Push/Right angle, Push/Rock, Push/Twist) during simulated driving. The persons with disabilities in the lower extremity have problems in operation of the vehicle because of functional impairments for controlling accelerator and brake pedal. Therefore, if hand control device is used for adaptive driving controls in persons with lower extremity loss, the disabled people could improve their quality of mobility life by driving a car. Twenty subjects were involved in this research to assess driving performance and EMG activities for operating accelerator and brake pedal by using four types of left hand controls in driving simulator. We measured EMG responses of six muscles(posterior deltoid, middle deltoid, biceps, triceps, extensor carpi radialis, and flexor carpi radialis) during pulling and pushing movement with four types of left hand controls for acceleration and braking. STISim Drive 3 program was used for evaluation test of four types of left hand control devices in straight lane course for time to reach target speed and brake reaction time. While operating the four types of left hand controls for acceleration, EMG activities of posterior deltoid in normal subjects were significantly increased(p < 0.05) compared to the disabled subjects. It was also found that EMG responses of triceps and posterior deltoid were significantly increased(p < 0.05) when using the Push/Right angle type than Push/Pull type. While operating the four types of left hand controls for braking, EMG activities of flexor carpi radialis and triceps in subjects with disability were significantly increased(p < 0.05) compared to the normal subjects. It was shown that muscle responses of posterior deltoid, middle deltoid and triceps were significantly increased when using the Push/Right angle type than Push/Rock type. Time to reach target speed and brake reaction time in subjects with disability was increased by 2.5% and 4.6% on average compared to normal subjects. The person with disabilities showed a tendency to relatively slow performance in acceleration at the straight lane course.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.19 no.1
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• pp.158-167
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• 2018

The role of S/W in weapon systems has been developed with various functions and complex structures. As the weapon system S/W is directly related to quick and accurate decision making of users, more accurate evaluation is required during the training. However, situation awareness of weapon system S/W users has only been assessed qualitatively such as by simple test or qualitative judgement. Therefore, this study suggests the 'Cognition Ratio' concept which represents the quantitative of users by combining ACT-R cognitive architecture to SA (Situation Awareness) and Fitts' Law based on the theory of cognitive engineering. The cognition ratio is a ratio of cognition among the whole cognitive behavior process including perception and psychomotor. Moreover, this study provides a systematic assessment process of situation awareness that will be applicable to various weapon system S/W for effective assessment.