• Journal of Intelligence and Information Systems
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• v.18 no.1
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• pp.23-38
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• 2012

There is a large difference between purchasing patterns in an online shopping mall and in an offline market. This difference may be caused mainly by the difference in accessibility of online and offline markets. It means that an interval between the initial purchasing decision and its realization appears to be relatively short in an online shopping mall, because a customer can make an order immediately. Because of the short interval between a purchasing decision and its realization, an online shopping mall transaction usually contains fewer items than that of an offline market. In an offline market, customers usually keep some items in mind and buy them all at once a few days after deciding to buy them, instead of buying each item individually and immediately. On the contrary, more than 70% of online shopping mall transactions contain only one item. This statistic implies that traditional data mining techniques cannot be directly applied to online market analysis, because hardly any association rules can survive with an acceptable level of Support because of too many Null Transactions. Most market basket analyses on online shopping mall transactions, therefore, have been performed by expanding the co-occurrence criteria of traditional association rule mining. While the traditional co-occurrence criteria defines items purchased in one transaction as concurrently purchased items, the expanded co-occurrence criteria regards items purchased by a customer during some predefined period (e.g., a day) as concurrently purchased items. In studies using expanded co-occurrence criteria, however, the criteria has been defined arbitrarily by researchers without any theoretical grounds or agreement. The lack of clear grounds of adopting a certain co-occurrence criteria degrades the reliability of the analytical results. Moreover, it is hard to derive new meaningful findings by combining the outcomes of previous individual studies. In this paper, we attempt to compare expanded co-occurrence criteria and propose a guideline for selecting an appropriate one. First of all, we compare the accuracy of association rules discovered according to various co-occurrence criteria. By doing this experiment we expect that we can provide a guideline for selecting appropriate co-occurrence criteria that corresponds to the purpose of the analysis. Additionally, we will perform similar experiments with several groups of customers that are segmented by each customer's average duration between orders. By this experiment, we attempt to discover the relationship between the optimal co-occurrence criteria and the customer's average duration between orders. Finally, by a series of experiments, we expect that we can provide basic guidelines for developing customized recommendation systems. Our experiments use a real dataset acquired from one of the largest internet shopping malls in Korea. We use 66,278 transactions of 3,847 customers conducted during the last two years. Overall results show that the accuracy of association rules of frequent shoppers (whose average duration between orders is relatively short) is higher than that of causal shoppers. In addition we discover that with frequent shoppers, the accuracy of association rules appears very high when the co-occurrence criteria of the training set corresponds to the validation set (i.e., target set). It implies that the co-occurrence criteria of frequent shoppers should be set according to the application purpose period. For example, an analyzer should use a day as a co-occurrence criterion if he/she wants to offer a coupon valid only for a day to potential customers who will use the coupon. On the contrary, an analyzer should use a month as a co-occurrence criterion if he/she wants to publish a coupon book that can be used for a month. In the case of causal shoppers, the accuracy of association rules appears to not be affected by the period of the application purposes. The accuracy of the causal shoppers' association rules becomes higher when the longer co-occurrence criterion has been adopted. It implies that an analyzer has to set the co-occurrence criterion for as long as possible, regardless of the application purpose period.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.19 no.11
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• pp.2179-2188
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• 1994

In this paper, we studied the deployment of AIN(Advanced Intelligent Network) that was recommended by ITU-T there are five methods of deployment. Here we divided these methods into two types. One is the direct connection with SCP(Service Control Point) and IP(Intelligent Peripheral) via No.7 and the other is the indirect connection with SCP and IP Through SSP(Service Switching Point). First, we suggested the structure of AIN SSP and defined S/W functional blocks. Second, we proposed H/W functional extension for interaction with IP. On the basis of the suggested structure, we mathematically evaluated and simulated two types of the deployment of AIN. In the result, we knew that, in comparison with the indirect method, the direct method was effective.

• Journal of Digital Convergence
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• v.10 no.1
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• pp.241-251
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• 2012

Despite the increasing importance that companies currently place on employee wellness, few studies have explored the impact of wellness on individual and team performance in the workplace. Drawing on the broaden-and-build theory, we hypothesize that wellness intention, wellness leadership, and wellness climate influence the performance of both individuals and teams. We tested our hypotheses using data collected from 495 employees of 81 teams in 11 Korean companies. Our analysis indicates that wellness leadership and wellness climate are meaningful interventions between perceived wellness and performance. Wellness intention did not impact perceived wellness. However, the interaction between wellness intention and wellness leadership impacted perceived wellness. Wellness climate negatively moderated the relationship between perceived wellness and performance.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.45 no.4
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• pp.342-348
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• 2017

In this paper, film cooling characteristics at supersonic free stream conditions were examined experimentally by applying an IR-thermography. Film cooling experiments were carried out in a free-jet facility at Mach number of 3.0 and with unit Reynolds number of $42.53{\times}10^6$ and $69.35{\times}10^6$ using wedge shaped film cooling model which has a converging film cooling nozzle. Film cooling efficiency was calculated by measuring the surface temperature of PEEK(Polyether Ether Ketone) and the effects of angle of attack and blowing ratios on the film cooling efficiency were examined. The measured wall temperature was significantly reduced by the film cooling flow compared with the results without the film cooling flow. The usefulness of film cooling was also confirmed by the surface heat flux calculated using the surface temperature history of PEEK. As the blowing ratio increases the protected area of PEEK was also expanded along the direction of free stream and film cooling flow.

• Journal of Educational Research in Mathematics
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• v.24 no.4
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• pp.537-554
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• 2014

In this study, we investigated a good way for teacher professional development. Based on this way, we designed teacher training program. We carried out teacher training program for 50 secondary school mathematics teachers in July 2014. In this teacher training courses, teachers conducted recording mathematics teaching-learning processes by dialogue between teacher and student according to Socratic method. We also shared the practices of teacher educators, teachers and colleagues. In this teacher training, we tried to cultivate teachers' abilities needed to a good mathematics instruction. And we aimed to equip the attitude that guided reflection on their mathematics class. Through the teacher training, teachers recognized the need to study on the thinking of students and take into account students' expected reaction on the part of learners. Also they developed an attitude as reflective practitioners and recognized the need of teacher learning communities for their professional development.

• Proceedings of the Korea Water Resources Association Conference
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• 2006.05a
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• pp.1112-1115
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• 2006

모바일 GIS를 홍수재해관리 시스템에 도입하기 위한 목적은 홍수에 대비한 신속한 상황대처 통해 인명 및 재산피해를 최소화하는데 있다. 모바일 GIS 시스템 구축의 기본 방향은 하천유역에 대한 행정업무 및 정보화 업무의 효율성을 높여 현장업무에서 실시간으로 제공되는 수문정보 및 지형정보에 대한 다양한 컨텐츠를 주민들이 쉽게 접근하여 서비스를 제공받을 수 있도록 하고 현장 실무자가 하천 수위 및 유량을 관리하는 데 있어 즉각적인 조치를 가능하도록 하기 위한 것이다. 본 연구에서 이동 클라이언트와 홍수재해관리시스템 서버간의 무선통신채널은 AP(Access Point)를 통한 WLAN이나 CDMA망의 모바일 네트워크 또는 차세대 휴대인터넷 망을 대상으로 하였다. 홍수재해관리시스템은 ArcIMS, HTML, Java Script를 이용하여 구축하고 웹 서비스를 위해 마이크로소프트사의 IIS(Internet Information System) 사용하며, ArcIMS의 정상적인 구동을 위해 JRE(Java Runtime Environment)를 설치하도록 하였다. 주요 GIS 기능은 줌인, 줌아웃, 팬, 속성정보 검색, 거리측정, 버퍼링 기능 등이고 Layer는 침수위험건물, 대피건물, 침수지역 건물용도, 건물, 도로, 수계, 침수예상지역(100, 200년 빈도), 위성영상, DEM, 행정경계 등이 포함되도록 하였다. 시스템 구축에 사용될 데이터는 수리수문학적 데이터(유출량, 강우강도, 대상지역의 면적, Manning 계수 등)와 대상지역의 수치지도, DEM, 고해상 위성영상, 문헌조사와 현장조사를 통해 얻은 자료를 바탕으로 구성하도록 하였으며, 수리수문학적 데이터와 DEM 데이터를 바탕으로 침수지역 데이터를 생성하고 문헌조사와 현장조사를 통해 얻은 속성정보와 디지털 지도인 공간정보를 연결하기 위해 디지털 지도에서 건물 Layer, 도로 Layer, 등고선 Layer, 수계 Layer를 추출하여 ArcGIS에서 Coverage로 변환하여 위상관계를 설정한 후 다시 Shape 파일로 변환하여 속성정보와 연결시키도록 데이터베이스 구축방안을 제시하였다. 이와 같이 본 연구에서는 홍수재해 관리시스템에서 모바일 GIS를 적용하기 위하여 Pocket PC를 탑재한 이동 클라이언트인 PDA에 GPS 모듈을 확장하여 GPS 위성으로부터 위치정보를 획득하고 지리정보를 제공하는 모바일 GIS 서버간에 XML 기술을 이용하여 수문정보 및 지형정보 서비스를 제공하는 방안을 제시하였다.

• Journal of Korea Multimedia Society
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• v.15 no.5
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• pp.606-614
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• 2012

Face detection using AdaBoost algorithm is one of the fastest and the most robust face detection algorithm so many improvements or extensions of this method have been proposed. However, almost all previous approaches deal with only frontal face and suffer from limited discriminant capability for inclined face because these methods apply the same features for both frontal and inclined face. Also conventional approaches for detecting inclined face which apply frontal face detecting method to inclined input image or make different detectors for each angle require heavy computational complexity and show low detection rate. In order to overcome this problem, a method for detecting inclined face using JointBoost is proposed in this paper. The computational and sample complexity is reduced by finding common features that can be shared across the classes. Simulation results show that the detection rate of the proposed method is at least 2% higher than that of the conventional AdaBoost method under the learning condition with the same iteration number. Also the proposed method not only detects the existence of a face but also gives information about the inclined direction of the detected face.

• The KIPS Transactions:PartB
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• v.17B no.2
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• pp.125-138
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• 2010

The purpose of this research is to enhance document recognition system which is essential for developing full-text retrieval system of the document image data stored in the digital library of a public institution. To achieve this purpose, the main tasks of this research are: 1) analyzing the document image data and then developing its image preprocessing technology and document structure analysis one, 2) building its specialized knowledge base consisting of document layout and property, character model and word dictionary, respectively. In addition, developing the management tool of this knowledge base, the document recognition system is able to handle the various types of the document image data. Currently, we developed the prototype system of document recognition which is combined with the specialized knowledge base and the library of document structure analysis, respectively, adapted for the document image data housed in National Archives of Korea. With the results of this research, we plan to build up the test-bed and estimate the performance of document recognition system to maximize the utilization of full-text retrieval system.

• The Journal of the Korea Contents Association
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• v.13 no.5
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• pp.146-158
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• 2013

The purpose of this study is to analyze the story-retelling structure of tablet PC-based applications that designed to help infants to create stories. Owing to the popularization and the usability of smart devices, infants have become from content consumers to creators who reconstruct stories in creative ways, based on the stories they heard. In those participatory process, infants experience enjoying stories independently and expanding the meaning of texts. Story-retelling is an adequate methodology that cultivates creativity, expressiveness, and literacy ability to infant. Consequently, this study investigates three types of story-retelling in , , and , and searches structure elements and methods of story-retelling in integrated approach. In conclusion, the story-retelling applications that provide 'creative gap' have educational value, because they allow infants to demonstrate imagination by filling in the gap and to realize the rule of stories.

• Journal of KIISE
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• v.44 no.8
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• pp.791-802
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• 2017

Competition in the modern CPU market has shifted from speeding up the clock speed of a single core to increasing the number of cores. As such, there is a growing interest in parallel programming to maximize the use of resources of many core processors. In this paper, we propose parallel programming models in Haskell to find an advisable parallel programming model for many-core environments. Specifically, we used Eval monad and Cloud Haskell to develop two versions of parallel programs: plagiarism detection and K-means. Then, we evaluated the performance of the developed programs in 32-core and 120-core environments. The results of our experiment show that the Eval monad is highly efficient in an environment with a small number of cores. On the other hand, the Cloud Haskell runtime shows 37% improvement over Eval monad and the scalability shows a 134% improvement over Eval monad as the number of cores increases.