• The Transactions of the Korean Institute of Power Electronics
• /
• v.6 no.5
• /
• pp.416-422
• /
• 2001

The BLDC(Brushless DC) Motor is characterized by linear torque to current and speed to voltage. It has low acoustic noise and fast dynamic response. Moreover, it has high power density with high proportion of torque to inertia in spite of small size drive. However, when armature current is commutated, the current ripple is generated by the motor inductance components in stator windings and back-EMF. This current ripple caused to torque ripple. Therefore, it is difficult to apply the BLDC motor to a precision servo drive system. In this paper, a new current control algorithm using fourier series coefficients is proposed. This proposed algorithm can minimize torque ripple due to the phase current commutation of BLDC motor. Simulation and Experimental results prove the effectiveness at the Proposed algorithm through comparison with the conventional unipolar PWM method.

• The Journal of the Korea Contents Association
• /
• v.20 no.4
• /
• pp.396-405
• /
• 2020

In this study, we used the big data of Voice of Customer (VOC) related to high-speed Internet products to look at the causes of perceived quality and the possibility of proactive service. In order to verify the possibility of proactive service, we collected VOC data from 13 facilities and equipment of a mobile communication service company, and then conducted 𝒙² test to verify that there was a statistically significant difference between the actual VOC observation values and expected values. We found statistical evidence that proactive service is possible through real-time monitoring for the six disability alarms among the 13 facilities and equipment, which are FTTH-R Equipment ON/OFF, FTTH-EV Line Error Detection, Port Faulty, FTTH-R Line Error Detection, Network Loop Detection, and Abnormal Limiting Traffic. Companies are able to adopt the proactive service to improve their market share and to reduce customer service costs. The results of this study are expected to contribute to the actual application of industry in that it has diagnosed the possibility of proactive service in the telecommunication service sector and further suggested suggestions on how to provide effective proactive service.

• Journal of the HCI Society of Korea
• /
• v.11 no.3
• /
• pp.5-12
• /
• 2016

The number of visually-impaired people using a smartphone is currently increasing with the help Text-to-Speech(TTS). TTS converts text data in a mobile application into sound data, and it only allows sequential search. For this reason, the location of buttons and contents inside an application should be determined carefully. However, little attention has been made on TTS service environment during the development of mobile newspaper application. This makes visually-impaired people difficult to use these applications. Furthermore, a mobile application interface which also reflects the desire of the low vision is necessary. Therefore, this paper presents a mobile newspaper interface which considers the accessibility and the desire of various visually impaired people. To this end, the proposed interface locates buttons with the consideration of TTS service environment and provides search functionality. The proposed interface also enables visually impaired people to use the application smoothly by filtering out the words that are pronounced improperly and providing the proper explanation for every button. Finally, several functionalities such as increasing font size and color reversal are implemented for the low vision. Simulation results show that the proposed interface achieves better performance than other applications in terms of search speed and usability.

• Korean Journal of Social Welfare
• /
• v.68 no.4
• /
• pp.225-246
• /
• 2016

This study aims to explore the theoretical and practical potentials of the late modern social space theories concerning deinstitutionalization issues in the field of the Mental Health. Deinstitutionalization, the process of converting the living space mentally ill people from facilities to the community, is a meaningful event realizing the modern ideology of human rights and welfare in social work territory. Although the continuos and accumulative efforts to realize the ideas of deinstitutionalization, which have focused on the ideological validity and the conditions and administrative supports needed for materialization, however, discussing the issues without analyzing late modern societal space neglects the constraints of the generic and comprehensive 'space' in which the deinstitutionalization can actually occur. Thus, this study attempts the following by analyzing the concrete reality of social space: focusing on deinstitutionalization in a larger social context, different from previous studies that discussed it on a normative and fragmentary level; and more concretely analyzing the realistic limits and challenges facing deinstitutionalization. In order to do this, previous literature related to deinstitutionalization is laid out and theories of late modern social space are studied. Based on this, the kinds of phenomenon that occur when this sort of late modern social space meets with the deinstitutionalization of mentally ill people are analyzed. Finally, based on the results, the study suggests several implications to realize the rights and welfare of mentally in the late modern space concerning deinstitutionalization.

• Journal of Music and Human Behavior
• /
• v.21 no.1
• /
• pp.69-87
• /
• 2024

This study investigated whether joint attention response behaviors in children with autism spectrum disorder (ASD) change in response to musical cues and reinforcing stimulus, and compared them with neurotypically developing (NT) children. The participants included 13 children with ASD and 14 NT children aged between 3 to 5 years. The study established six task conditions, involving cues (verbal vs. musical) for responding to joint attention (RJA) behaviors and reinforcing stimulus (verbal vs. sound vs. musical) for social referencing behaviors. These tasks were presented 12 times with two repetitions each. The results of the study showed that providing musical cues during the RJA phase increased levels of RJA in children with ASD, consistent with prior studies. Subsequently, musical reinforcing stimuli increased the frequency of social referencing behaviors in these children. This indicates that musical stimuli can extend beyond mere sensory cues, helping individuals to understand and respond to social and emotional cues from others. Moreover, these musical stimuli could serve as effective social reinforcement factors for this population.

• Journal of Life Science
• /
• v.19 no.3
• /
• pp.317-321
• /
• 2009

Down syndrome (DS) results from overexpressed genes on an extra copy of human chromosome 21. Among various phenotypes seen in DS patients, mental retardation, such as learning and memory deficits, is a major factor that prevents DS individuals from leading fully independent lives. The Dyrk1A gene that plays a critical role in neurodevelopment has been isolated from chromosome 21, and transgenic mice with over-expression of Dyrk1A show severe hippocampal dependent learning and memory defects. In the present study, as an initial step to test the treatment of Dyrk1A dependent mental retardation phenotypes in model animals, we isolated human Dyrk1A specific lentiviral short hairpin RNA (shRNA) that inhibits the exogenous human Dyrk1A expression, but not the endogenous mouse expression in transgenic mice with human Dyrk1A overexpression. This limited and specific repression of exogenous human Dyrk1A will prove to be valuable information, if Dyrk1A dependent learning and memory defects in DS patients could be treated or at least ameliorated in vivo.

• Journal of Oral Medicine and Pain
• /
• v.26 no.3
• /
• pp.301-308
• /
• 2001

지금까지 여러 가지 형태의 기기를 이용하여 보고된 사람의 교합력은 그 최대치가 매우 다양하다. 본 연구에서는, 교합력을 측정하기 위하여 새로운 측정기기를 개발하였다. 본 기기를 이용하여 전치부 교합력 측정 시에는 대칭적으로 최대한 물도록 하악을 유도하여 최대 교합력을 측정하였고, 구치부는 편측으로 물도록 하악을 유도하여 최대 교합력을 측정하였다. 교합 시 치아간 수직고경은 15.1mm 였다. 측정기기 내 strain gauge를 사용하여 전기저항의 변화를 힘으로 전환하였다. 마이크로 프로세서가 수치를 계산하면 액정화면에 수치가 표시된다. 실험실 내 기기교정 검사에서는 50kg과 100kg의 부하를 가하였다. 개발된 교합력 측정기기의 임상적 신뢰도를 시험하기 위해 건강한 치과대학 재학생 10명을 대상으로 최대 교합력을 측정 하였다. 이 새로운 측정기기로 측정된 교합력은 이전연구에서 기록되었던 것보다 더 높은 수치가 나왔다. 또한 제1대구치와 전치부에서 최대 교합력을 측정한 경우 실험자 내와 실험자 간에 통계적으로 유의한 신뢰성을 얻을 수 있었다. 본 기기는 안정적이고 조작성이 쉽다고 판명되었다. 그러므로, 본 기기는 더 큰 연구 집단의 선별검사에 매우 유용하게 사용할 수 있을 것이며, 또한 치주질환이 있는 치아나 임플란트, 악관절 장애를 가진 환자의 교합력 측정과 같이 특정된 경우의 교합력 측정에도 유용할 것이다.

• Journal of the Korean BIBLIA Society for library and Information Science
• /
• v.15 no.2
• /
• pp.161-176
• /
• 2004

To examine the current states of community survey performance with its contents and methods, a questionnaire survey was made for 92 public libraries in Seoul, Gyeonggi, and Incheon area. 47 libraries(70%) have conducted community survey during last 5 years. The frequency has increased since 2001. Considering the content item as separate entity, the average is 1.7 times per library. The main purpose of the survey was to understand the resident's need and a questionnaire survey method was applied dominantly. Problems involved with the lack of budget, time, and the librarian's ability are identified as obstacles. Based on the analysis, recommendations such as acknowledgement, administrations and financial support, establishment of standards, education and train information are suggested to promote the community survey.

• Toxicological Research
• /
• v.17 no.1
• /
• pp.65-71
• /
• 2001

The key targets of endocrine disruptors are nuclear hormone receptors, which bind to steroid hormones and regulate their gene transcription. A yeast-based steroid hormone receptor gene trascription assay was previously developed for the evaluation of chemicals with endocrine modulating activity. The yeast transformants used in this assay contain the human estrogen receptor along with the appropriate steroid response elements upstream of the $\beta$-galactosidase reporter gene. We tried to evaluate several natural and synthetic steroids of their potential to interact directly with the steroid receptor. Some putative endocrine disruptors, including nonylphenol, are weakly estrogenic. But the combined treatment oj these chemicals with di-(2-ethylhexyl)phthalate (DEHP) significantly increased the $\beta$-galactosidase activity in the yeast transformant. These results suggest that we also have to consider the synergistic effects of endocrine disruptors. In this study, we showed that yeast-based bioassay is a valuable tool for screening potential endocrine disruptors and quantitative determination of estrogenicity. And the possibility that the estrogen receptor binds multiple environmental chemicals adds another level of complexity to the interaction between the endocrine disruptors and the human hormone system.

• Proceedings of the Korea Information Processing Society Conference
• /
• 2000.10a
• /
• pp.673-676
• /
• 2000

본 논문에서는 네트워크 트래픽 분석은 물론 자원을 관리하고 서버 및 특정 서비스에 대하 분석 자료를 제공하는 통합 시스템을 자바 언어로 구현하였다. SNMP 지원 모듈과 TCPdump 모듈, 그리고 시스템 관리 명령 모듈 등을 이용하여 구성 관리, 성능 관리, 장애 관리 및 시스템 자원 관리와 같은 상세 정보의 제공과 함에 다양한 자료 수집과 통계 분석을 통해 상세 보고서를 생성한다. 뿐만 아니라, 관리 대상 범위를 도메인 별로 구분하여 자료 수집을 독립시킴으로써 관리를 위한 트래픽이 전체 네트워크에 영향을 미치지 않도록 설계하였고, 실시간 모니터링은 물론 DB 에 최소화된 자료를 유지함으로써 네트워크 및 시스템에 대한 영속적인 관리 및 통계가 가능하도록 하여 운영의 항구성과 안정성, 분석의 정확성과 일치성, 사용의 편의성과 효용성을 제공하고자 하였다.