• Journal of Biomedical Engineering Research
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• v.38 no.2
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• pp.74-81
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• 2017

The purpose of this study was to investigate the EMG characteristics of driver's upper extremity and driving performance for manipulating brake and accelerator pedal by using left and right hand control devices during simulated driving. The people with disabilities in the lower limb have problems in operation of the motor vehicle because of functional loss for manipulating brake and accelerator pedal. Therefore, if hand control device is used for adaptive driving controls in people with lower limb impairments, the disabled people can improve their quality of life by driving a motor vehicle. Six subjects were participated in this study to evaluate driving performance and muscle activities for operating brake and accelerator pedal by using two different hand controls (steering column mounted hand control and floor mounted hand control) in driving simulator. We measured EMG activities of six muscles (posterior deltoid, middle deltoid, triceps, biceps, flexor carpi radialis, and extensor carpi radialis) during pushing and pulling movement with different hand controls for acceleration and braking. STISim Drive 3 software was used for the performance test of different hand control devices in straight lane course for time to reach target speed and brake reaction time. While pulling the hand control lever toward the driver, normalized EMG activities of middle deltoid, triceps and flexor carpi radialis in subjects with disabilities were significantly increased (p < 0.05) compared to the normal subjects. It was also found that muscle responses of posterior deltoid were significantly increased (p < 0.05) when using the right hand control than left hand control. While pushing the hand control lever forward away from the driver, normalized EMG activities of posterior deltoid, middle deltoid and extensor carpi radialis in subjects with disability were significantly increased (p < 0.05) compared to the normal subjects. It was shown that muscle responses of middle deltoid, biceps and extensor carpi radialis were significantly increased when using the right hand control than left hand control. Brake reaction time and time to reach target speed in subjects with disability was increased by 12% and 11.3% on average compared to normal subjects. The subjects with physical disabilities showed a tendency to relatively slow acceleration at the straight lane course.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.31 no.2A
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• pp.176-186
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• 2006

In this paper, we propose an enhanced symbol detector algorithm for 2.45GHz LR-WPAN(Low-Rate Wireless Personal Area Network) receiver. Because the frequency offset of $\pm$80ppm on 2.45GHz band is recommended in IEEE 802.15.4 LR-WPAN(Low-Rate Wireless Personal Area Network) specification, a symbol detector algorithm having stable operation in the channel environment with large frequency offset is required. For robustness to the frequency offset, non-coherent detection-based symbol detector algorithm is typically applied in the LR-WPAN receiver modem. However, the noncoherent symbol detector has increased performance degradation and hardware complexity due to squaring loss of I/Q squaring operation. Therefore we propose a coherent detection-based symbol detector algorithm with frequency offset compensation using a preamble symbol. The proposed algorithm is more suitable for LR-WPAN receiver aimed at low-cost, low-power and low-complexity than the non-coherent symbol detector, since it can reduce performance degradation due to squaring loss of I/Q squaring operation and implementation complexity. Simulation results show that the proposed algorithm has performance improvement of about 1dB in various channel environments.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.34 no.4
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• pp.1289-1298
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• 2014

Pavement crack sealing method, which is one of the methods to maintain and repair the road, prevents the extending of cracks by repairing cracks in its early occurrence and has already been applied to many roadworks in advanced foreign country for a long time. But in the conventional crack sealing method, traffic accidents occur frequently during the repair because it's commonly performed on the heavy traffic road or highway. It also has some difficulties in securing the safety of workers from the risk of burns caused by heated sealant. In an effort to solve these problems, automated pavement crack sealing machines such as ARMM, OCCSM, TTLS have been developed in advanced foreign country since early 1990s. Also APCS in 2004 and ACSTM in 2013 were already developed domestically. However, since these automated crack sealers developed from a number of research institutions have different test-bed conditions and productivity measurement models, it's difficult to compare and evaluate them objectively. In this study, the image processing time of the respective machines and the movement time of each motion on the work process were estimated by using fully autonomous mapping and semi-automatic mapping in order to measure the productivity in the same environmental conditions. In addition, the productivity measurement test-bed reflected domestic road characteristics was designed to estimate and compare the productivity of the automated crack sealing machines.

• The Journal of the Acoustical Society of Korea
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• v.39 no.2
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• pp.131-136
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• 2020

Wake Up Word (WUW) is a short utterance used to convert speech recognizer to recognition mode. The WUW defined by the user who actually use the speech recognizer is called user-defined WUW. In this paper, to recognize user-defined WUW, we construct traditional Gaussian Mixture Model-Hidden Markov Model (GMM-HMM), Linear Discriminant Analysis (LDA)-GMM-HMM and LDA-Deep Neural Network (DNN)-HMM based system and compare their performances. Also, to improve recognition accuracy of the WUW system, a threshold method is applied to each model, which significantly reduces the error rate of the WUW recognition and the rejection failure rate of non-WUW simultaneously. For LDA-DNN-HMM system, when the WUW error rate is 9.84 %, the rejection failure rate of non-WUW is 0.0058 %, which is about 4.82 times lower than the LDA-GMM-HMM system. These results demonstrate that LDA-DNN-HMM model developed in this paper proves to be highly effective for constructing user-defined WUW recognition system.

• Journal of the Korea Society of Computer and Information
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• v.17 no.1
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• pp.1-10
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• 2012

Improving operating frequency of processors is no longer today's issues; a multiprocessor technique which integrates many processors has received increasing attention. Currently, high-performance processors that integrate 64 or 128 cores are developing for large data processing over 2, 4, or 8 processor cores. This paper proposes an optimal many-core processor for synthesizing guitar sounds. Unlike the previous research in which a processing element (PE) was assigned to support one of guitar strings, this paper evaluates the impacts of mapping different numbers of PEs to one guitar string in terms of performance and both area and energy efficiencies using architectural and workload simulations. Experimental results show that the maximum area energy efficiencies were achieved at PEs=24 and 96, respectively, for synthesizing guitar sounds with sampling rate of 44.1kHz and 16-bit quantization. The synthesized sounds were very similar to original guitar sounds in their spectra. In addition, the proposed many-core processor was 1,235 and 22 times better than TI TMS320C6416 in area and energy efficiencies, respectively.

• Journal of the Institute of Electronics Engineers of Korea SC
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• v.46 no.1
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• pp.1-9
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• 2009

In this paper, a 2.4 GHz doppler radar system consisting of a doppler radar sensor and a baseband module were designed to detect heart beat and respiration signal without direct skin contact. The doppler radar system emits RF signal of 2.4 GHz toward human chest, and then detects phase modulation of the reflected signal so as to investigate cardiopulmonary activities. The heartbeat and respiration signals acquired from I/Q channels of the doppler radar system are applied to the pre-processing circuit, the amplification circuit, and the offset circuit of the baseband module. The designed system was tested on mouse, rabbit and mankind, which have different range of heart rates and respiration signals, to evaluate detection accuracy of the system. ECG acquisition system and respiration transducer were used to generate the reference signal. In our experiments, a performance of detection were found to be high in the case that the subject stays still. In this paper, we confirmed that non-contact heart beat and respiration detection using the doppler radar has the possibility and limitation according to distance, cardiopulmonary activities, range of heart rates and respiration.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.28 no.1
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• pp.1-9
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• 2017

In this paper, ETRI's $0.25{\mu}m$ GaN MMIC process is introduced and the fabricated results of X-Band 3 W power amplifier MMIC are discussed. The one-stage X-Band 3 W power amplifier MMIC using the $0.25{\mu}m$ GaN MMIC devices has been designed and fabricated. From the fabricated GaN MMIC, the characteristics of the $0.25{\mu}m$ GaN MMIC process and devices are evaluated and analyzed. The X-band power amplifier MMIC shows output power of 3.5 W, gain of 10 dB, and power-added efficiency of 35 %.

• Journal of agricultural medicine and community health
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• v.44 no.4
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• pp.209-219
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• 2019

Objectives: This study investigated musculoskeletal symptoms in upper limbs according to the working environment (job stress) of dental hygienists and examine their relationship with upper limb functions. Methods: The subjects include 198 dental hygienists in dental hospitals and dental clinics in Pusan and Gyeongnam. The questionnaire was consisted of general characteristics of the subjects, job stress, musculoskeletal symptoms in upper limbs and function (Disability Measurement Tool for Upper Extremity Disorders-11, DASH-11). Results: The study was analyzed their musculoskeletal symptoms in upper limbs according to their general characteristics and found that the symptoms occurred in the neck (39.4%), the shoulders (54.6%), elbows (14.7%), and the hands (50.0%). Job stress was associated with upper limb functions (DASH-11) (model 3, B=5.210, p=0.012) and repeated elbow bending and spreading posture was associated with DASH-11 (model 3, B=6.561, p=0.029). Elbow symptoms were associated with DASH-11 in the upper limbs (B=10.679, p=0.003). Conclusion: Dental hygienists are experiencing limitations of upper limb function due to job stress. In particular, even if the correction of their uncomfortable posture is significantly related to the job stress and upper limb function, in order to improve the upper limb function of the dental hygienist, efforts to reduce the job stress as well as the uncomfortable posture are necessary.

• Journal of the Korean housing association
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• v.11 no.2
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• pp.149-163
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• 2000

노인소비자들은 나이와 함께 기능적인 능력이 감퇴하면서 주택내의 환경이 그들의 한계와 장애를 보완해 줄 수 있게 좀 더 지원적이기를 기대한다. 이러한 노인그룹을 포함하여 모든 사용자에게 독립적이고, 안전하며, 편리한 생활환경을 조성해 주는 것이 유니버셜 디자인이다. 이 연구의 목적은 유니버셜 디자인 개념으로 개발 된 혁신적인 욕실용품들, 즉 높이가 조절되어 앉거나 서서 사용하는 장점 등을 갖춘 세면대와 높이조절이 되는 이동식 샤워기가 장착된 걸어서 들어가며, 접이식 의자가 있는 등의 장점을 가진 욕조에 대한 소비자 의견의 검토이다. 피험자는 미국에 사는 미국노인과 한국노인(50세이상-79세까지)으로 합계 58명이었다. 실험장소는 미국서부소도시 대학의 유니버셜 디자인 연구실로, 이 대학의 협력으로 이곳에 장착된 신개발 설비를 이용하였다. 실험시기는 1997년 5월부터 11월 사이(봄, 가을)로 소비자 의견조사는 3단계로 이루어졌다. 먼저 1단계 설문조사에서는 피험자 거주주택의 욕실환경, 피험자의 목욕방법, 건강과 안전, 새로운 욕실설비에 대한 소비자 의견 등이 조사되었다. 2단계는 실제로 선정 된 욕실설비의 사용실험으로 피험자가 옷입은 상태에서 목욕을 가정하여 선택된 설비의 사용동작을 하면서(비디오 촬영) 조사자의 조사표에 의한 질문에 답하였다. 3단게는 2단계의 사용실험 후 유니버셜 디자인 된 욕실설비의 가정 내 도입의사 등의 조사를 하였다. 위에서 설명한 3단계의 소비자 의견조사 및 실험에서 얻은 결과는 다음과 같았다. 1) 미국거주 미국노인과 한국노인의 비교에서 한국노인의 평균 신장이 3cm정도 작았고, 2개이상의 욕실을 가진 비율과 학벌, 독신거주비율은 미국노인이 다소 높았고, 욕조 소유율은 한국노인이 높았다. 2) 새로운 욕실 설비에 대한 소비자 의견은 미국과 한국노인 모두 유니버셜 디자인된 새 설비의 장점을 인정하였다. 욕조와 세면조가 매력적이라 평하였고 샤워조작기가 색상구분으로 도운물과 찬물인지가 편하며, 접이식 의자가 유용하며, 문 달린 욕조의 안전 손잡이와 욕조가장자리를 잡고 안전하게 출입한다고 했다. 그러나 욕조길이와 높이에서 두 나라간에 차가 있어 앞으로 치수에 대한 것이 연구과제로 지적되었다. 3) 욕실 설비 개발 시 유니버셜 디자인 용품에 요구되는 목표는 안전하게 쓸 수 있고, 가령에 따른 신체장애요소가 커버되어 스스로 사용가능하고, 사용상 번거로움이 없어 정신적 스트레스를 주지않는 것이어야 하겠다. 4) 선택된 유니버셜 디자인 욕실설비는 표준치수의 현 욕조위치에 장착이 가능하여 앞으로 현 주택에의 교체가 가능하였다. 5) 선택된 유니버셜 디자인 욕실설비는 인체치수와 문화가 다른 두 나라 노인 모두 긍정적으로 평가하여 앞으로의 국제적 보급이 기대되었다.

• Journal of the Korean Recycled Construction Resources Institute
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• v.1 no.3
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• pp.246-254
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• 2013

This study is purposed to verify the safety of the floor of the children's playground using polyolefin foam waste and rubber paving. The critical fall height, walking suitability, long term physical fatigue expectation and slipperiness were tested. Polyolefin foam wastes in thickness of 30mm, 50mm and 70mm were prepared with paving the rubber paving materials in 12mm and 15mm thickness respectively. The test on the critical fall height was carried out according to KS G 5758:2009. The floor hardness test equipment (O-Y HMA) was used for the test on hardness of the floor from a viewpoint of walking suitability and fatigue. A portable slipperiness tester (ONO PPSM) was used for slipperiness test. It was revealed from the test that the floor made of the polyolefin foam waste and rubber paving were considerably safe from a viewpoint of impact absorption. With regards to the hardness of the floor, it was shown the excellent performance in the aspects of walking and fatigue for male. But it was not suitable with walking on the shoes(middle heels) for female. And they will be very fatigue if they were in a long time walking or standing. As far as the slipperiness is concerned, it was shown that it was comparatively safe for the ordinary motions even though the surface was wet.