• Journal of the Korean Institute of Intelligent Systems
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• v.11 no.3
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• pp.223-230
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• 2001

Since self-organizing map (SOM) preserves the topology of ordering in input spaces and trains itself by unsupervised algorithm, it is Llsed in many areas. However, SOM has a shortcoming: structure cannot be easily detcrmined without many trials-and-errors. Structure-adaptive self-orgnizing map (SASOM) which can adapt its structure as well as its weights overcome the shortcoming of self-organizing map: SASOM makes use of structure adaptation capability to place the nodes of prototype vectors into the pattern space accurately so as to make the decision boundmies as close to the class boundaries as possible. In this scheme, the initialization of weights of newly adapted nodes is important. This paper proposes a method which optimizes SASOM with genetic algorithm (GA) to determines the weight vector of newly split node. The leanling algorithm is a hybrid of unsupervised learning method and supervised learning method using LVQ algorithm. This proposed method not only shows higher performance than SASOM in terms of recognition rate and variation, but also preserves the topological order of input patterns well. Experiments with 2D pattern space data and handwritten digit database show that the proposed method is promising.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2015.05a
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• pp.166-167
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• 2015

수동적 온톨로지 구축은 해당 도메인의 지식을 가진 전문가가 필요하고, 시간적인 소모가 크다. 또한 완성된 온톨로지의 수동적인 지속적 개선은 상당한 비용을 초래할 수 있다. 그래서 온톨로지의 자동 구축과 지속적 자기 개선 방법이 하나의 해결책이 될 수 있을 것이다. 따라서, 이 논문에서는 기계 학습을 통한 온톨로지 구축의 자동화 방법과 지속적 자기 개선 모델을 소개하고자 한다.

• Journal of Astronomy and Space Sciences
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• v.26 no.4
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• pp.467-478
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• 2009

The super-geomagnetic storms called 2003 Halloween event globally occurred during the period of 29 through 31 which are the following days when the solar flares of X18 class exploded on 28 October 2003. The S4 index from GPS signal strength and the peak electron density ($NmF_2$) from GPS tomography method are analyzed according to the date. The occurrences of the cycle slip and scintillation in the GPS signals are 1,094 and 1,387 on 28 and 29 October, respectively and these values are higher than 604 and 897 on 30 and 31 October. These mean the ionospheric disturbances are not always generated by the period of geomagnetic storm. Therefore, GPS S4 index is useful to monitor the ionospheric disturbances. Behaviors of ionospheric electron density estimated from GPS tomography method are analyzed with the date. At UT = 18 hr, the maximum $NmF_2$ is shown on 28 October. It agrees with $NmF_2$ variation measured from Anyang ionosonde, and the GPS signal are better condition on 30 and 31 October than 28 October. In conclusion, GPS signal condition is relation with geomagnetic activities, and depend upon the variation of the electron density. We will study the long-term data to examine the relationship between the GPS signal quality and the electron density as the further works.

• Journal of the Korea Convergence Society
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• v.10 no.7
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• pp.133-139
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• 2019

This study investigated what type of destination image on Facebook increases positive attitude towards the destination and desire to travel. More specifically, we hypothesized that Facebook user's public self-consciousness will moderate the advertising effect, so we tested the difference in attitude towards the destination and willingness to visit and recommend based on the type of destination image (presence/absence of a tourist in the image) and user's public self-consciousness (high/low). As a result, when a tourist was present in the photo, positive attitude toward destination was higher than when absent. In addition, the high public self-consciousness group showed greater attitude toward destination and higher willingness to visit and recommend than low public self-consciousness group when a tourist was present in the image. However, the low public self-consciousness group showed no difference depending on the presence of a tourist. This research not only is academically significant as it experimentally tested advertising effect depending on type of destination image and Facebook user's public self-consciousness, but also holds practical significance as it suggests advertisement method to consider consumer's predisposition.

• Journal of Conservation Science
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• v.27 no.3
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• pp.291-300
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• 2011

Archaeomagnetic dating method is used to assign a date to the archaeological remains in which burnt soil is found by measuring the changes in terrestrial magnetism with the thermal remanent magnetization retained in burnt soil. This method, in particular, is quite useful to determine an age of the archaeological remains in which no properties are found, which makes it difficult to assigning a date. Hemp kiln and lime kiln fall under remains of these features, and 21 and 5 archaeomagnetic data from both kilns respectively were obtained by measuring the- remanent magnetization in burnt soil samples that are extracted in hemp kilns and lime kilns in the country. The results of archaeomagnetic dating with these data show the age range of the hemp kilns is between the late 10th century A.D. and the middle of the 19th century, and that of the lime kilns is between the early 16th century A.D. and the middle of the 18th century. The factor that the number of data collected from the hemp kilns was comparatively more than those from the lime kilns might affect the result, however corresponding to the fact that hemp had been used for a long period of time, the period of hemp kiln are widely spread over the chronological table. And the archaeomagnetic dating of lime kiln, in view of archaeological periods, is not only in accord with the late Joseon period when the tombs with lime-soil mixture barrier in trend; this is also telling that its width of archaeological period is comparatively narrow.

• The Korean Journal of Petroleum Geology
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• v.7 no.1_2 s.8
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• pp.7-12
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• 1999

A new high-resolution rnagnetotelluric (MT) survey was conducted for pull-apart basin analysis (Cretaceous Eumsung Basin), combined with surface sedimentological results. Two cross-basinal MT profiles represent an asymmetric form with a subbasin in the southeastern part. These basinal architectures are well compatible with paleoflow directions and facies transitions of surface sedimentology. The results also suggest that the basin fills reflect pull-apart opening with rapid subsidence of the central blocks. Combined with the surface sedimentological data on asymmetric lithofacies distribution, facies transitions, and paleoflow directions of the alluvio-lacustrine systems, the MT data help explain basin-fill processes during the basin formation. For petroleum exploration and basin analysis, the high-frequency MT technique can be a useful substitute for the costly burden of a seismic-reflection survey on land.

• Proceedings of the Korea Institute of Convergence Signal Processing
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• 2000.08a
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• pp.117-120
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• 2000

본 논문은 이동로봇이 주행 중 발생하는 heading 오차를 지자기센서를 이용하여 보정하고 주행을 정확히 제어하는 것에 관한 것이다. 일반적으로 이동로봇의 주행제어는 여러 원인에 의한 부정확성을 내포하고 있다. 예를 들어 바퀴의 부정확한 기계적 정렬, 기어의 헐거워짐, 센서 신호의 잡음과 오차, 바퀴의 미끄러짐, 평탄하지 않는 표면에 의한 제도변동 등이다. 따라서, 이동명령어 수행 시 이동로봇의 heading이 의도된 대로 유지되는지를 측정하는 오차 검출이 필요하며 이를 위한 센서 본 논문에서는 지자기센서를 이용하여 오차를 보정하였다. 실험은 무선 원격 제어되는 이동로봇에 지자기 센서를 부착하여 자계의 영향이 비교적 적은 평탄한 옥외에서 수행하였고, 실험 결과를 통해 지자기 센서를 이용한 이동로봇의 heading 오차 보정과 주행제어효과를 보여주었다.

• Proceedings of the Korean Information Science Society Conference
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• 2010.06d
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• pp.136-141
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• 2010

차량 이동으로 인해 변화하는 지구 자기장을 감지하여 차량을 검지하고, 이를 기반으로 속도를 계산하는 지자기 센서노드가 활발히 연구됨으로 인해, 텔레매틱스 및 ITS (Intelligent Transportation Systems) 분야로서의 그 응용분야가 급속히 확대되고 있다. 본 논문에서는 지자기 센서를 이용하여 차량 검지 및 속도 계산을 위한 센서 네트워크의 구성과 그에 따른 차량 검지 및 속도 계산 알고리즘을 설계 및 구현한다. 이를 위해, 센서 네트워크 및 각 알고리즘에서 고려해야 하는 것들을 정리하고, 이들을 고려한 방법을 구현하며, 시뮬레이션을 이용하여 평가함으로써 설계의 유용함을 보인다.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.18 no.6
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• pp.229-235
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• 2018

Research on indoor location tracking technology using smart phone is actively being carried out. Especially, in order to display the movement path of the smartphone on the map, the azimuth angle should be estimated by using the geomagnetic sensor built in most smart phones. Due to the distortion of the magnetic field due to the surrounding steel structure and the inclination of the smartphone, the estimation error of azimuthal angle may be occurred. In this paper, we propose a correction method of the geomagnetic sensor at the stationary state and a correction method for the inclination of the smartphone. We also propose a method to correct the azimuth error due to the difference between the magnetic north and the grid north.

• The Journal of the Korea Contents Association
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• v.16 no.1
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• pp.642-654
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• 2016

The purpose of this study was analyze the characteristics of self-management of the physical activity questionnaire elementary and develop self-management. To do this, from the average student is selected to receive training in physical education gifted students, and to cover up the children who are acting as an athlete in the current schools participated in a variety of students. Professional meetings, inductive categorization, item analysis, exploratory factor analysis and confirmatory factor analysis conducted, the verification was carried out between different groups discriminant validity for verification. As a result, physical activity self-management factor is the support of the parents of elementary school students, exercise management, life management, interest, self-confidence, support of parents, personal management were six factors determined to be a total of 24 questions. In addition, Gifted children was higher than in all the sub-factors of physical activity self-management in the general child population. As a result, we ensure the validity of the test to diagnose physical activity as a self-managed by first responders schools.