• KSII Transactions on Internet and Information Systems (TIIS)
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• 제11권4호
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• pp.1841-1865
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• 2017

This paper proposes a new interference mitigation scheme for device-to-device (D2D) communications underlaying a cellular network. The object of the proposed scheme is to determine the number of data streams, a precoding matrix, and a decoding matrix of D2D networks so as to maximize the system capacity given the number of data streams of a cellular network while satisfying the constraint of the inter-system interference from D2D networks to the cellular network. Unlike existing interference mitigation schemes based on the interference alignment technique, the proposed scheme operates properly regardless of the number of data streams of a cellular network and moreover it does not require changing the precoding and decoding matrices of a cellular network. The simulation results demonstrate that the proposed scheme significantly increases the system capacity by mitigating the intra- and inter-system interference.

• 한국통신학회논문지
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• 제32권6B호
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• pp.325-333
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• 2007

설계된 HW IP를 응용수준에서 제어하기 위해 OS상에서의 디바이스 드라이버가 요구된다. 디바이스 드라이버의 개발은 하드웨어와 OS에 대해 시스템 개발자의 정확한 이해가 필요하며 하드웨어 개발 기간과 비용의 많은 부분을 차지한다. 본 논문에서는 OS정보, 하드웨어 특징정보를 이용하여 OS에 따른 디바이스 드라이버를 인터페이스 회로와 함께 자동 생성하는 시스템의 구축에 대해 제시한다. 제안한 시스템에서는 효율적인 디바이스 드라이버 자동생성을 위해 디바이스 드라이버의 기본골격과 함수 모듈 코드, 헤더파일 테이블 등을 라이브러리로 구축하여 입력 데이터에 따라 선택되어 디바이스 드라이버가 자동생성 되도록 하였다. 제안된 방법으로 ARM922T 코어에 삼성 3.5인치 TFT-LCD를 장착하여 커널버전 ARM-Linux 2.4.19를 탑재한 후 디바이스 드라이버를 자동 생성하여 커널에 등록한 뒤 하드웨어에 write 연산을 실행하는데 걸린 시간을 비교한 결과 매뉴얼로 설계한 디바이스 드라이버에 비해 1.12%의 감소를 보였다. 커널 컴파일 후의 코드 사이즈는 0.17%의 증가를 보였다. 생성된 디바이스 드라이버는 응용프로그램 레벨에서 하드웨어를 제어할 때 발생하는 지연시간을 고려하면 실제 성능의 차이가 없음을 보인다. 본 논문에서 제안한 시스템을 사용하여 시스템 개발기간을 단축할 수 있다.

• 한국융합학회논문지
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• 제8권12호
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• pp.291-298
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• 2017

최근 차량내부에서는 운전과 직접적인 관련이 적은 다양한 편의장치들이 도입되고 있으며, 이러한 장치들의 조작환경을 하나로 통합하려는 노력이 시도되고 있다. 본 논문은 자동차 내의 다양한 편의장치에 대한 통합 조작환경을 구축하기 위해 자기유변유체(magnetorheological fluid; MR 유체)를 이용한 햅틱장치를 제안하고자 한다. 이를 위해 먼저 차량 편의 조작장치들이 갖는 회전과 상하 수직 운동을 동시에 구현할 수 있는 메커니즘을 고안하고 햅틱 기능을 부여하기 위해 MR 유체를 도입함으로써 하나의 장치로 다기능 조작이 가능한 햅틱 장치를 고안한다. 장치에서 발생하는 반향력에 대한 모델링에 근거하여 MR 햅틱 장치의 자료를 설계하고 시작품을 제작한다. 그리고 완성된 장치의 회전 및 수직 운동에 대한 응답 성능시험을 수행하여 제안된 모델을 검정한다. 또한 힘 반향 성능을 구현하기 위해 장치의 반향력 모델을 이용한 역모델 보상기(inverse model compensator)를 설계한다. 마지막으로 실제 자동차의 여러 편의 기능의 작동과정을 고려하여 햅틱 반향력 맵을 구축하고 제어기와 연동하여 제작된 햅틱 장치의 힘반향(force-feedback) 제어 성능을 평가한다.

• 한국화재소방학회논문지
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• 제29권4호
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• pp.81-88
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• 2015

본 연구에서는 다양한 화재실험에서 광학 연기밀도 측정을 위하여 광소멸법을 이용한 저가형 장치가 개발되었다. 저가형 장치의 상대적 측정 정확도는 He-Ne 레이저, 포토디텍터 및 다양한 광학부품을 이용한 고가의 표준장치에 의해 측정된 연기밀도의 비교를 통해 평가되었다. 저가형 장치는 레이저 모듈, 포토셀 그리고 아크릴 보드로 구성되었다. 연기농도의 조절이 용이한 연기 발생장치 실험을 통해, 저가형 장치는 표준장치에 비해 ${\pm}10%$의 범위 내에서 연기밀도를 측정할 수 있음을 확인하였다. 저가 장치의 신뢰성은 또한 폴리에틸렌 화염을 이용한 실험에서도 확인되었다. 결론적으로 개발된 저가형 장치는 연기밀도 측정을 위한 간편한 설치 및 실시간 측정과 함께 고가의 표준장치를 대신하여 사용될 것으로 기대된다.

• 문화기술의 융합
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• 제8권5호
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• pp.29-37
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• 2022

2017년 새롭게 제정된 유럽의 새 의료기기 규제법인 MDR은 기존의 CE 적합성 인증을 받은 의료기기 제품들이 새로운 CE의 MDR규정에 맞춰 2024년 5월까지 인증을 받도록 요구하고 있다. 새로운 MDR 적합성 요구사항은 기존보다 강화된 의료기기 임상평가 및 임상 조사를 요구하며 또한 문서화된 시판후 임상 추적 자료의 제출을 요구한다. 한국의 의료기기 업체들도 새로운 MDR 요구사항을 맞춰 적합인정을 받아야 하나, 새로우 규정을 정확히 이해하지 못하여 산업계의 혼란은 계속 되고 있다. 본 연구에서는 한국과 미국의 의료기기 관련 규정을 알아보고, 또한유럽의 의료기기법인 MDR을 기존의 유럽 의료기기 지침인 MDD와 비교함으로써 유럽 의료기기법의 요구 사항들을 이해하는데 도움이 되고자 한다.

• 한국염색가공학회지
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• 제25권1호
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• pp.65-69
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• 2013

PET fabrics of various luster, fiber thickness(denier), and weaving structure were dyed at the same conditions and determined their grey scale by using naked eyes, computer color matching (CCM) system, and real industry color (RIC) device to evaluate the effectiveness of RIC device developed in this study. As for the luster of fabrics, bright PET showed more differences when compared with semi-dull and full-dull. PET in both naked eyes and RIC device since the RIC device provide the real image of fabrics to observers. As for the fiber thickness, the results of naked eyes and RIC device were very similar while the result of CCM showed lower color grade. Finally, as for the weaving structures of PET fabrics, all the test results by naked eyes, CCM, and RIC device showed almost same grey scales. In these regards, the RIC device developed in this study was comparable to naked eyes by providing the real image of fabrics, however it was difficult to compare the very bright colors such as yellow and fiber thickness(denier) and weaving structure of fabrics.

• Archives of Plastic Surgery
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• 제35권4호
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• pp.393-399
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• 2008

Purpose: Chronic infected wounds sustained over 4 weeks with exposed tendon or bone are difficult challenges to plastic surgeons. Vacuum assisted closure (VAC) device has been well used for the management of chronic wounds diminishing wound edema, reducing bacterial colonization, promoting formation of granulation tissue and local blood flow by negative pressure to wounds. But Commercial ready-made VAC device might have some difficulties to use because of its high expenses and heavy weight. So we modified traditional VAC device with silver dressing materials as topical therapeutic agents for control of superimposed bacterial wound infection such as MRSA, MRSE and peudomonas. Methods: We designed the modified VAC device using wall suction, 400 cc Hemovac and combined slow release silver dressing materials. We compared 5 consecutive patients' data treated by commercial ready-made VAC device(Group A) with 11 consecutive patients' data treated by modified VAC device combined with silver dressing materials(group B) from September 2004 to June 2007. Granulation tissue growth, wound discharge, wound culture and wound dressing expenses were compared between the two groups. Results: In comparison of results, no statistical differences were identified in reducing rate of wound size between group A and B. Wound discharge was significantly decreased in both groups. Modified VAC device with silver dressing materials showed advantages of convenience, cost effectiveness and bacterial reversion. Conclusion: In combination of modified VAC device and silver dressing materials, our results demonstrated the usefulness of managing chronic open wounds superimposed bacterial infection, cost effectiveness compared with traditional VAC device and improvement of patient mobility.

• 한국응급구조학회지
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• 제22권1호
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• pp.49-59
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• 2018

Purpose: The purpose of this study was to develop an assistant device for the promotion of bag-valve-mask ventilation based on a non-equivalent control group pre-test and post-test design. Methods: The experimental tool was a mask assistance device developed by the researchers. Data were analyzed using SPSS 21.0 with the cardiopulmonary resuscitation (CPR) evaluation program from August 18 to 30, 2016. The research tools included general, hand-related, and ventilation-related characteristics. Results: Before and after using the mask assistance device, the tidal volume increased by 64 mL (p<.001) from 461.76 mL to 525.86 mL. The tidal volume for control was 477.86 mL, and there was a statistical difference (p<.05). The ventilation frequency in device users was 10 times per minute for a total of 20 ventilations with before 10.65 after 10 times, and that of the control group was before 10.36 times after 10 times; there was no difference in both groups(p>.05). The accuracy of the assistance device was $81.72{\pm}30.86%$, which was a very high value. However, the accuracy of ventilation in the control group with no assistance device was $18.97{\pm}32.44%$, which was a very low accuracy rate. Conclusion: This study's results suggested utilizing the newly-developed mask assistance device in CPR, and showed increases in tidal volume and accuracy of ventilation using the bag-valve-mask ventilation equipment. The general and hand-related characteristics did not have any effect, so the use of the device proved to increase the efficacy in all users.

• 대한의용생체공학회:의공학회지
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• 제44권5호
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• pp.315-323
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• 2023

The objective of this study is to identify the selective application targets for reporting on details of supply of class 1 and 2 medical devices as part of the improvement of the reports on details of supply of medical device system, and to analyze its effectiveness. Therapeutic materials covered by health insurance and secondhand medical devices were chosen based on the transparency of health insurance coverage and the management of medical device distribution. As a result, approximately 85% of groups can be excluded from the reporting requirements compared to reporting all items under Class 1 and 2 medical devices. This is expected to enhance the efficiency of supply reporting tasks. Additionally, the information on supply details managed by the regulatory authority can be utilized for statistical analysis and periodic monitoring, serving as fundamental data for the development of medical device-related policies and research in the field of medical devices.

• Journal of Cerebrovascular and Endovascular Neurosurgery
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• 제25권3호
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• pp.275-287
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• 2023

Objective: Flow diverting stents (FDS) are a validated device in the treatment of intracranial aneurysms, allowing for minimally invasive intervention. However, after its approval for use in the United States in 2011, post-market surveillance of adverse events is limited. This study aims to address this critical knowledge gap by analyzing the FDA Manufacturer and User Facility Device Experience (MAUDE) database for patient and device related (PR and DR) reports of adverse events and malfunctions. Methods: Using post-market surveillance data from the MAUDE database, PR and DR reports from January 2012-December 2021 were extracted, compiled, and analyzed with R-Studio version 2021.09.2. PR and DR reports with insufficient information were excluded. Raw information was organized, and further author generated classifications were created for both PR and DR reports. Results: A total of 2203 PR and 4017 DR events were recorded. The most frequently reported PR adverse event categories were cerebrovascular (60%), death (11%), and neurological (8%). The most frequent PR adverse event reports were death (11%), thrombosis/thrombus (9%) cerebral infarction (8%), decreased therapeutic response (7%), stroke/cerebrovascular accident (6%), intracranial hemorrhage (5%), aneurysm (4%), occlusion (4%), headache (4%), neurological deficit/dysfunction (3%). The most frequent DR reports were activation/positioning/separation problems (52%), break (9%), device operates differently than expected (4%), difficult to open or close (4%), material deformation (3%), migration or expulsion of device (3%), detachment of device or device component (2%). Conclusions: Post-market surveillance is important to guide patient counselling and identify adverse events and device problems that were not identified in initial trials. We present frequent reports of several types of cerebrovascular and neurological adverse events as well as the most common device shortcomings that should be explored by manufacturers and future studies. Although inherent limitations to the MAUDE database are present, our results highlight important PR and DR complications that can help optimize patient counseling and device development.