• 한국지능시스템학회논문지
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• 제25권2호
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• pp.97-104
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• 2015

본 논문에서는 중량물을 들어 올리는 작업자를 돕기 위한 2차원 와이어 구동식 중량물 권양 시스템과 퍼지제어기를 제안한다. 2차원 와이어 구동식 중량물 권양 시스템은 사람이 전체 제어루프에 포함된 인간지원시스템의 일종이다. 기존 인간지원시스템 대부분의 제어 방식이 사용자의 특성을 고려하지 못하는 단점을 해결하기 위하여 물건을 들어 올리는 작업자의 힘을 덜어주어야 하는 요구조건과 사람의 작업 모션을 고려한 퍼지제어기 설계 방식을 제안한다. 실험을 통해 제안된 시스템의 2차원 작업 모션의 성능을 검증한다.

• 한국IT서비스학회지
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• 제15권4호
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• pp.73-83
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• 2016

Pedestrian safety was recently highlighted with a yellow carpet, a yellow-colored pavement material prepared for children waiting for signals for pedestrian crossing, without validation of its efficiency in practice. It was a promising device likely to assist highway safety by stimulating pedestrian to step on the yellow-colored area; it was generally called nudge effects. This paper delivers a study conducted to check the effectiveness of yellow carpet in three different aspects in vehicle driver's perspective by applying the newly introduced information technology (IT) service: Visual Attention Software (VAS). It was assumed that VAS developed by 3M in the United States should be able explain the Korean drivers' visual reaction behaviors since technology embedded in VAS was developed based on and proved by other various international countries and continents in the world. A set of pictures was taken at thirteen different field sites in seven school zone areas in the Seoul metropolitan area before and after the installation of a yellow carpet, respectively. Sets of those pictures were analyzed with VAS, and the results were compared based on the selective safety measures: the likely focusing on standing pedestrians (waiting for a pedestrian's green signal time) affected by its background (yellow-colored pavement) contrasting him or her. The test results from a set of before-and-after comparison analyses showed that the placement of yellow carpet would (1) increase 71% of driver's visual attention on pedestrian crossing areas and (2) change the sequential order of visual attention on that area 2.4 steps ahead. The findings would enhance deployment of such promising efficiency and thus increase children safety in pedestrian crossing. The result was promising to highlight the way to support the changes in conservative traffic safety engineering field by applying the advanced IT services, while much robust research was recommended to overcome the limitation of simplification of this study.

• 한국정밀공학회지
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• 제27권6호
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• pp.82-89
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• 2010

Ankle-foot orthosis with an artificial pneumatic muscle which is intended for the assistance of plantarfelxion torque was developed. In this study, power pattern of the device in the various pneumatics and the effectiveness of the system were investigated. The pneumatic power was provided by ankle-foot orthosis controlled by user‘s physiological signal, that is, muscular stiffness in soleus muscle. This pneumatic power can assist plantarflexion torque of ankle joint. The subjects performed maximal voluntary isokinetic plantarflexion motion on a biodexdynamometer in different pneumatics, and they completed three conditions: 1) without wearing the orthosis, 2) wearing the orthosis with artificial muscles turned off, 3) wearing the orthosis activated under muscular stiffness control. Through these experiments, we confirmed the effectiveness of the orthosis and muscular stiffness control using the analyzing isokinetic plantarflexion torque. The experimental results showed that isokinetic torques of plantarflexion motion of the ankle joints gradually increased in incremental pneumatic. The effectiveness of the orthosis was -7.26% and the effectiveness of the muscular stiffness control was 17.83% in normalized isokinetic plantarflexion torque. Subjects generated the less isokinetic torques of the ankle joints in wearing the orthosis with artificial muscles turned off, but isokinetic torques were appropriately reinforced in condition of wearing the orthosis activated under muscular stiffness control(17.83%) compared to wearing the orthosis(-7.26%). Therefore, we respect that developed powered orthosis is applied in the elderly that has weak muscular power as the rehabilitation equipment.

• 한국항행학회논문지
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• 제17권6호
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• pp.777-784
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• 2013

다른 종류의 센서에서 생산되는 데이터를 하나의 정보로 종합하는 공정으로 멀티 센서 데이터 융합이 연구되고 있으며 다양한 플랫폼에서 활용되고 있다. 항공기도 여러 종류의 센서들을 장착하고 있으며 항공전자 체계에서 이를 통합하여 관리하고 있다. 항공기 센서의 성능이 높아지면서 항공전자 관점에서 센서 정보의 통합이 점차 증가하고 있다. 센서에서 생산된 데이터를 하나의 융합된 정보로 항공기 조종사에게 전시 장비로 시현하기 위한 융합을 담당하는 소프트웨어 관점에서 정보 융합을 다루는 연구는 활성화 되지 않고 있다. 항공기에서 정보 융합의 목적은 올바른 전투상황을 조종사에게 제공하여 임무를 수행하는 데에 필요한 결정을 돕고 이를 위한 조종 업무량을 최소화하는 것이다. 본 논문에서는 다양한 센서들이 운용되는 항공전자 시스템의 멀티센서데이터 융합을 위한 소프트웨어 관점에서 센서들이 생산하는 데이터가 사용자에게 종합된 정보 형태로 제공되기 위한 구조를 보인다.

• 한국정보기술학회논문지
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• 제17권4호
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• pp.131-136
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• 2019

시작장애인은 일상생활에서 시각저하로 인하여 색상, 지폐 금액 확인, 온도 판별 등의 불편을 겪는다. 그리하여 시각장애인을 도와주기 위한, 광학 카메라와 열화상 카메라를 이용한 시스템을 제안한다. 광학카메라는 특징 추출을 이용하여 색상 판별, 지폐 금액 확인하며, 온도 판별을 위해서 열화상 카메라를 이용한다. 버튼을 이용하여 색상, 지폐, 온도 모드를 선택하면, 해당 정보를 스피커를 통하여 음성으로 알려준다. 색상은 16가지, 지폐는 4가지, 온도는 4단계로 구분할 수 있으며, 각기 정확도는 90%이다. 향후 입력 영상 블록화, 머신러닝, 열화상 카메라 상위 버전을 통해 정확도를 개선할 수 있다. 또한, 휴대하기 편하게 지팡이에 부착하여 시각 장애인들이 더 편리하게 사용 할 수 있도록 개선 예정이다.

• 한국전기전자재료학회논문지
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• 제35권5호
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• pp.445-451
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• 2022

Ultrasonic sensor is suitable as a next-generation autonomous driving assist device because its lower price compared to that of other sensors and its sensing stability in the external environment. Although Pb(Zr, Ti)O₃ (PZT)-relaxor ferroelectric system has excellent piezoelectric properties, the change in capacitance is large in the daily operating temperature range due to the low phase transition temperature. Recently, many studies have been conducted to improve the temperature stability of ferroelectric ceramics by controlling the grain size and crystal structure, so it is necessary to study the effect of the grain size on the piezoelectric properties and the temperature stability of PZT-relaxor ferroelectric system. In this study, the piezoelectric properties, phase transition temperature, and temperature coefficient of capacitance (TCC) of 0.9 Pb(Zr_1-xTi_x)O₃-0.1 Pb(Zn_1/3Nb_2/3)O₃ (PZT_x-PZN) ceramics with various grain sizes were investigated. PZT_x-PZN ceramics with larger grain size showed higher piezoelectric properties and temperature stability, and are expected to be suitable for ultrasonic devices in the future.

• 한국의류산업학회지
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• 제24권5호
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• pp.647-654
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• 2022

Wearable devices come in a variety of shapes and sizes in numerous fields in numerous fields and are available in various forms. They can be integrated into clothing, gloves, hats, glasses, and bags and used in healthcare, the medical field, and machine interfaces. These devices keep track individuals' biological and behavioral data to help with health communication and are often used for injury prevention. Those with hearing loss or impaired vision find it more difficult to recognize an approaching person or object; these sensing devices are particularly useful for such individuals, as they assist them with injury prevention by alerting them to the presence of people or objects in their immediate vicinity. Despite these obvious preventive benefits to developing Internet of Things based devices for the disabled, the development of these devices has been sluggish thus far. In particular, when compared with people without disabilities, people with hearing impairment have a much higher probability of averting danger when they are able to notice it in advance. However, research and development remain severely underfunded. In this study, we incorporated a wearable detection system, which uses an infrared proximity sensor, into a backpack. This system helps its users recognize when someone is approaching from behind through visual and tactile notification, even if they have difficulty hearing or seeing the objects in their surroundings. Furthermore, this backpack could help prevent accidents for all users, particularly those with visual or hearing impairments.

• Journal of Chest Surgery
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• 제56권1호
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• pp.6-13
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• 2023

Background: Coronavirus disease 2019 (COVID-19) has been found to cause life-threatening respiratory failure, which can progress to irreversible lung damage. Lung transplantation can be a life-saving treatment in patients with terminal lung disease (e.g., acute respiratory distress syndrome caused by infection). This study aimed to present the clinical course and results after initial lung transplantation in patients with severe COVID-19 who did not recover even with optimal medical care. Methods: From August 2019 to February 2022, this study enrolled 10 patients with COVID-19 (5 men; median age, 55.7 years) who underwent lung transplantation at a single center in Korea. All patients' characteristics, clinical pathway, overall survival, complications, and operative data were collected and analyzed. Results: Veno-venous extracorporeal membrane oxygenation or an oxygenator in a right ventricular assist device circuit was applied to 90% of the patients, and the median length of extracorporeal life support before operation was 48.5 days. There were no cases of mortality after a median follow-up of 372.8 days (interquartile range, 262.25-489 days). The major complications included the requirement for postoperative extracorporeal membrane oxygenation support in 2 cases (20%), re-transplantation in 1 case (10%), and re-exploration due to bleeding in 2 cases (20%). During the follow-up period, 3 out of 10 patients died. Conclusion: Excellent early outcomes were observed for patients who underwent lung transplantation. Thus, lung transplantation can be an effective and feasible treatment for patients with end-stage lung disease caused by COVID-19.

• 한국통신학회논문지
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• 제39B권7호
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• pp.479-490
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• 2014

하지근력증강로봇은 인간의 하체에 착용하여 보행능력을 강화하거나 보조하기 위한 장비다. 보행능력을 향상하기 위해 로봇은 착용자의 걷는 움직임을 감지하고 이에 적합한 로봇의 동작을 구동한다. 본 논문에서는 로봇이 착용자의 움직임을 감지하는 방법을 소개하고, 감지된 데이터를 착용자의 현재 보행단계를 의미하는 보행단계상태 정보로 변환하는 보행단계구분 알고리즘을 제시한다. 로봇은 보행단계상태 정보에 따라 현재 필요한 제어모드를 결정하고 로봇구동기를 작동하기 때문에 잘못된 정보가 전달된다면 로봇은 착용자의 보행능력을 향상할 수 없거나 착용자에게 오히려 불편을 줄 수 있다. 따라서 보행단계구분 알고리즘은 항상 정확한 정보를 제공할 수 있어야 한다. 하지만 본 연구에서 사용하는 센서장치의 경우 작은 움직임에도 민감하게 반응하는 특성이 있어 센서데이터를 임계기준으로 구분하는 방법으로는 항상 정확한 보행단계상태 정보를 구할 수 없다. 이러한 특성을 극복하면서 정확한 정보를 제공하기 위해 확률적 구분 방법을 응용한 나이브-플렉시블 베이지안 보행단계구분 알고리즘을 제안하였고, 실험을 통해 제안 방법의 정확성을 비교 분석하였다.

• 대한의용생체공학회:의공학회지
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• 제26권6호
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• pp.393-398
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• 2005

An electromechanical type is the most useful mechanism in the various pumping mechanisms. It, however, requires a movement converting system including a ball screw, a helical cam, or a solenoid-beam spring, which makes the device complex and may lessen reliability. Thus, the authors have hypothesized that an electromagnetic actuator mechanism can eliminate the movement converting system and that thereby enhance the mechanical reliability and operative simplicity of an electro­pneumatic pump. The purpose of this study was to show a novel application of electromagnetic actuator mechanism in pulsatile pump and to provide preliminary data for further evaluations. The electromagnetic actuator consists of stators with a single winding excitation coil and movers with a high energy density neodymium-iron-boron permanent magnet. A 0.5mm diameter wire was used for the excitation coil, and 1000 turns were wound onto the stators core with parallel. A prototype of extracorporeal electro-pneumatic pump was constructed, and the pump performance tests were performed using a mock system to evaluate the efficiency of the electromagnetic actuator mechanism. When forward and backward electric currents were supplied to the excitation coil, the mover effectively moved back and forth. The nominal stroke length of the actuator was 10mm. The actuator dimension was 120mm in diameter and 65mm in height with a mass of 1.4kg. The prototype pump unit was 150mm in diameter, 150mm in thickness and 4.5kg in weight. The maximum force output was 70N at input current of 4.5A and the maximum pump rate was 150 beats per minute. The maximum output was 2.0 L/minute at a rate of 80bpm when the afterload was 100mmHg. The electromagnetic actuator mechanism was successfully applied to construct the prototype of extracorporeal electro­pneumatic pump. The authors provide the above results as a preliminary data for further studies.