• KSII Transactions on Internet and Information Systems (TIIS)
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• 제7권5호
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• pp.1131-1145
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• 2013

Energy detection is a widely used method for spectrum sensing in cognitive radios due to its simplicity and accuracy. However, it is severely affected by the noise uncertainty. To solve this problem, a blind multiband spectrum sensing scheme which is robust to noise uncertainty is proposed in this paper. The proposed scheme performs spectrum sensing over the total frequency channels simultaneously rather than a single channel each time. To improve the detection performance, the proposal jointly utilizes the likelihood function combined with Gerschgorin radii of unitary transformed covariance matrix. Unlike the conventional sensing methods, our scheme does not need any prior knowledge of noise power or PU signals, and thus is suitable for blind spectrum sensing. In addition, no subjective decision threshold setting is required in our scheme, making it robust to noise uncertainty. Finally, numerical results based on the probability of detection and false alarm versus SNR or the number of samples are presented to validate the performance of the proposed scheme.

• 한국태양에너지학회 논문집
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• 제31권1호
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• pp.59-67
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• 2011

This paper is focused on the effect of indoor temperature rise according to the use of windows and blinds in double skin facade in summer. For the experiment, we set up the mock-up of double skin facede and measuring temperature and solar radiation. Total 7 cases were used for measuring solar transmittance and indoor temperature rise. When the venetian blind was not installed, solar transmittance was 44.5%, and solar transmittance for the case that installed the venetian blind (angle 0) was 22.5%. Cases that opened inner and outdoor windows for ventilation showed lower indoor temperature rise than cases with closed windows. In addition, Case 5 (opened inner and outdoor windows with the venetian blind (angle 0) to reduce solar transmittance) indicated lower indoor temperature rise than Case 3(opened inner and outdoor windows). Consequently, Case 5 which uses inner and outdoor window for ventilation and venetian blind to reduce solar transmittance is the most effective way to reduce indoor temperature rise among all cases tested in this research.

• Journal of Information Processing Systems
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• 제13권3호
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• pp.448-463
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• 2017

Multimedia is a ubiquitous and indispensable part of our daily life and learning such as audio, image, and video. Objective and subjective quality evaluations play an important role in various multimedia applications. Blind image quality assessment (BIQA) is used to indicate the perceptual quality of a distorted image, while its reference image is not considered and used. Blur is one of the common image distortions. In this paper, we propose a novel BIQA index for Gaussian blur distortion based on the fact that images with different blur degree will have different changes through the same blur. We describe this discrimination from three aspects: color, edge, and structure. For color, we adopt color histogram; for edge, we use edge intensity map, and saliency map is used as the weighting function to be consistent with human visual system (HVS); for structure, we use structure tensor and structural similarity (SSIM) index. Numerous experiments based on four benchmark databases show that our proposed index is highly consistent with the subjective quality assessment.

• 감성과학
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• 제11권1호
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• pp.113-122
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• 2008

본 연구에서는 고감성 의류로 사용되는 국내.외 남성용 소모직물 40종의 시료를 이용하여 이들 소모직물의 물성을 비교.분석하였다. 이들 시료는 1차시료 14개와 2차 시료 26개로 나누어지며 국내와 국외 시료로 구분하여 비교.분석하였다. 물성분석은 Blind field test를 이용하여 전문위원단에 의해 주관적인 물성 평가를 실시하여 국내.외 남성용 소모직물의 물성을 비교.분석하였다. Blind field test는 촉감(부드러움, 탄력감), 색상(선명도, 심색미), 외관(깨끗함, 자연광택), 비교 선호도 등으로 4개군으로 test는 총 7개의 평가항목으로 나누어 전문평가단에 의해 주관적으로 평가하였다.

• 한국ITS학회 논문지
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• 제23권2호
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• pp.173-188
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• 2024

자율주행차량(AV)의 기술 발전으로 실도로 내 자율주행이 가능해졌지만, 주변 요소로 AV의 인지 범위 또는 능력이 제한되는 인지 음영으로 완전한 자율주행에 어려움이 있다. 오늘날 Lv 4+ 자율주행 테스트 시나리오를 개발하기 위해서는 실제 도로에서 발생할 수 있는 다양한 인지 음영 상황을 파악하고 대비 전략을 구상하는 것이 중요하다. 따라서, 본 연구는 미국 캘리포니아 차량관리국(DMV)의 AV 사고 데이터를 통해 자율주행 모드 활성화 여부에 따라 AV와 일반차량의 사고 형태와 특성을 비교하고, AV 제어권 전환 데이터를 단계적으로 분류하여 인지 음영으로 인한 제어권 전환의 유형과 실제 사례를 도출하였다. 분석 결과, AV의 안전 운전 기동으로 일반 차량과 다른 사고 유형이 나타났으며, 3가지 유형의 인지 음영 사례를 파악하였다. 본 연구 결과는 Lv 4+ 자율주행 테스트 시나리오 개발의 중요한 기초자료가 될 것이며, 다양한 인지 음영이 고려된 테스트 시나리오를 통해 상황별 인지 음영을 해소하는 효율적인 전략을 마련할 수 있다. 이를 통해 실제 도로에서의 AV 주행 안전성을 효과적으로 평가하고 향상할 수 있을 것으로 기대된다.

• 전자공학회논문지SC
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• 제43권6호
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• pp.9-15
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• 2006

최근 로봇 개발의 현황을 살펴보면 인간과 로봇이 공존하면서 인간이 로봇으로부터 서비스를 받을 수 있는 로봇의 개발이 지속적으로 증가하는 추세다. 그 중에서도 특히 관심을 끌고 있는 것은 복지 로봇에 관한 연구이다. 현재 가장 일반화되어 있는 복지 로봇은 시각 장애인의 주행을 도와주는 안내 로봇이며 장애물을 인식하여 안전한 경로를 제공하는 것을 목적으로 한다. 본 논문에서는 장애물 충돌회피의 기능뿐만 다양한 센서를 장착하여 환경 정보를 파악하여 사용자에게 가장 안전한 이동방향과 이동 속도를 제시한다. 또한 지도 정보를 이용하여 사용자에게 가장 친숙하고 안전한 주행 경로를 선택하는 안내 로봇을 제시한다.

• KIEAE Journal
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• 제13권4호
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• pp.3-10
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• 2013

This study aims to identify convenient surrounding of the hospital room to be improved by specifically focusing on light environment and to examine a change of inflow of the daylight in the hospital room by using blind and light shelf device as base data of preliminary research for comprehending the relationship between healing environment and natural day light. Simulation analysis on previous facilities and the installation of horizontal light shelf that derives the inflow of day light has been specifically referred by using ECOTECT2011 program. In case of C-facility that mostly adjoined to exterior spaces, it was shown to be closer to a proper uniformity factor when an angle was controlled on the light shelf with blind installed at the same time. However, it was not overall appropriate because of visual displeasure occurred from inflow of much day light. In conclusion, it is the form of flat surface such as H-facility that provides an effect after installing the device to derive day light. Especially, it was shown that interior day light environment was improved when installing blind and controlling the angle at the same time.

• Journal of Mechanical Science and Technology
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• 제18권11호
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• pp.1900-1908
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• 2004

A human-friendly interactive system that is based on the harmonious symbiotic coexistence of human and robots is explored. Based on interactive technology paradigm, a robotic cane is proposed for blind or visually impaired travelers to navigate safely and quickly through obstacles and other hazards faced by blind pedestrians. Robotic aids, such as robotic canes, require cooperation between human and robots. Various methods for implementing the appropriate cooperative recognition, planning, and acting, have been investigated. The issues discussed include the interaction between humans and robots, design issues of an interactive robotic cane, and behavior arbitration methodologies for navigation planning.

• 한국멀티미디어학회논문지
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• 제7권6호
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• pp.791-797
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• 2004

We proposed a novel digital video watermarking that embeds dual watermarks in the block DCT domain to solve the deadlock problem. Daul watermarks are composed of private watermarks and robust blind watermarks. Firstly, private watermarks are embedded into the lowest AC coefficients of the P or B-frames in accordance with the motion direction gained from a previous frame. Secondly, blind watermarks that have the robustness are inserted into the DC coefficients of the I-frames using a private key made from temporal I-frame motion information. Thus, when a deadlock situation occurs, the proposed algorithm can efficiently solve the problem. Experimental results confirmed that the proposed algorithm can produce good subjective and objective results for MPEG coding with a variety of bit rates. Furthermore, the proposed watermarking algorithm can potentially be applied to broadcasting monitoring systems due to its simplicity and high robustness.

• 대한인간공학회지
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• 제30권6호
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• pp.739-747
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• 2011

Objective: The present study evaluated information presentation methods applicable to a wearable Braille display in terms of performance and satisfaction measures. Background: A Braille display wearable at a finger can improve accessibility of information for the blind by presenting information in real time. Method: A Braille display with six pins operated by DC servomotors was developed to simulate four information presentation methods(active, stationary, simultaneous, and sequential methods). An evaluation experiment was conducted with 16 participants(8 normal and 8 blind participants) by using three objective measures(reaction time, RT, unit: sec; recognition time, CT, unit: sec; correct response percentage, CP) and two subjective measures(overall satisfaction, OS; perception easiness, PE) with a 7-point scale. Results: The average RTs and CTs of the active and stationary methods were significantly shorter than those of the simultaneous and sequential methods for the blind participants. Also, the average CPs, OSs, and PEs of the active and sequential methods were significantly higher than those of the stationary and simultaneous methods. Conclusion: The active and sequential methods were preferred to the other methods for the blind. Application: The performance characteristics identified in the present study for the four braille display methods can be utilized to develop an effective wearable Braille display system.