• 제목/요약/키워드: Complex parts

검색결과 921건 처리시간 0.026초

궤도차량 변속기 출력 축 지지구조에 따른 베어링 수명 영향 평가에 대한 연구 (A Study on the Lifetime Assessment of Bearings According to the Output Shaft Supporting Structures in Transmissions of a Tracked Vehicles)

  • 박종원;김형의
    • 한국신뢰성학회지:신뢰성응용연구
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    • 제11권4호
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    • pp.331-342
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    • 2011
  • The transmission of tracked vehicles performs complex functions as steering, shifting, braking, etc. and the system level life time has been a key influenced by the number of sub-parts like as gear assembly, torque converter, clutches, bearings and so on. In particular, the mechanical type steering system in tracked vehicle has impact shock torques in steering shift and those kind of shock torques can effect on the durability of many sub-parts in power train system. The field failure modes of gear assembly, steering assembly and the bearings of output shaft appear as a very complex phenomenon. In this study, the actual failure, which may occur in field, of the transmission was investigated comprehensively and that the endurance test on the resulting output shaft bearing failure analysis and life assessment was performed. Life time test method used in this study, developed for the purpose of the internal usage, and under these testing techniques the impact of the each bearing damage, which used in tracked vehicle transmission left / right outputs of different structures, was analyzed.

Skin Segmentation Using YUV and RGB Color Spaces

  • Al-Tairi, Zaher Hamid;Rahmat, Rahmita Wirza;Saripan, M. Iqbal;Sulaiman, Puteri Suhaiza
    • Journal of Information Processing Systems
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    • 제10권2호
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    • pp.283-299
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    • 2014
  • Skin detection is used in many applications, such as face recognition, hand tracking, and human-computer interaction. There are many skin color detection algorithms that are used to extract human skin color regions that are based on the thresholding technique since it is simple and fast for computation. The efficiency of each color space depends on its robustness to the change in lighting and the ability to distinguish skin color pixels in images that have a complex background. For more accurate skin detection, we are proposing a new threshold based on RGB and YUV color spaces. The proposed approach starts by converting the RGB color space to the YUV color model. Then it separates the Y channel, which represents the intensity of the color model from the U and V channels to eliminate the effects of luminance. After that the threshold values are selected based on the testing of the boundary of skin colors with the help of the color histogram. Finally, the threshold was applied to the input image to extract skin parts. The detected skin regions were quantitatively compared to the actual skin parts in the input images to measure the accuracy and to compare the results of our threshold to the results of other's thresholds to prove the efficiency of our approach. The results of the experiment show that the proposed threshold is more robust in terms of dealing with the complex background and light conditions than others.

A big picture view of precision nutrition: from reductionism to holism

  • Kwon, Oran
    • Journal of Nutrition and Health
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    • 제52권1호
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    • pp.1-5
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    • 2019
  • Purpose: This review describes the historical changes in nutrition philosophy from a reductionist to a holistic approach during the $20^{th}$ century. Also, the role and efficient use of a holistic approach to precision nutrition are discussed. Results: Over the past century, significant progress has been made in human nutrition research, unraveling fundamental mechanisms of single nutrients on single targets or pathways. This kind of a reductionist approach has helped to save populations from nutrient deficiency diseases and improve associated health outcomes in large parts of the world. However, a new set of nutrition problems, like obesity and diet-related chronic diseases, are growing each year worldwide, increasing the financial burden on the health care system. A linear cause-effect association between single nutrients and a single physiologic effect, is insufficient to solve the complex nutrition-health relationships. Research that involves a more holistic rather than reductionist approach is needed to tackle a new set of nutrition problems. Recent advances in technology, informatics, and statistical methods are enabling an understanding of the diversity of individuals and the complex interactions between foods and human bodies, leading to the concept of "precision nutrition." Conclusion: The emerging goal of precision nutrition is to provide tailored dietary advice for maintaining health and preventing obesity and diet-related chronic diseases. The parts are already being installed. To grab the complexity, reductionism and holism must be used interdependently.

환경친화형 주거단지지 계획에 관한 의식조사 - 공동주택 거주자와 전문가를 대상으로 - (A Survey on the Residents' and Experts' Consciousness to Planning of the Environment-Friendly Apartment Complex)

  • 정유선;윤정숙
    • 한국주거학회논문집
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    • 제13권4호
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    • pp.81-88
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    • 2002
  • The purpose of this study is to accumulate basic data to establish planning direction and planning factors for the environment-friendly apartment complex. For this purpose, the survey has been conducted to residents living in an apartment housing and graduate students, architects and research experts in the field. The major findings of this study are as follows; 1) The basic concept of planning factors for environment-friendly apartment complex are energy saving, resources saving, minimizing environment pollution, natural harmony, regional identity and pursuit of residents' health & amenity. 2) For the planning factors of environment-friendly apartment complex, the residents had a great regard for aspect of Low-Impact (energy saving, resources saving, minimizing environment pollution). The experts, on the other hand, had a great regard for aspect of High-contact (natural harmony, regional identity). 3) It was increase of prime cost that the residents and experts regarded as the most important problem of planning and purchasing of environment-friendly apartment. It thus appears that the promotion of environmental consciousness of residents taking in the portion of increased cost is crucial parts and also that the role of the connected aspects such as administration, construction companies and residents must be redefined in order to manage problems caused in process of the development of it.

프레임 차량의 주행진동 저감을 위한 프레임 부시 복소 동강성 결정에 관한 연구 (A Study on Determination of Complex Stiffness of Frame Bush for Ride-Vibration Improvement of Body-on-Frame Vehicle)

  • 정면규;김기선;김광준;황인진
    • 한국소음진동공학회:학술대회논문집
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    • 한국소음진동공학회 2005년도 추계 학술대회논문집(수송기계편)
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    • pp.194-199
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    • 2005
  • Body-on-frame type vehicle has a set of frame bushes which are installed between body and frame fur vibration Isolation. Such frame bushes are important vibration transmission paths to passenger space. In order to reduce the vibration level of passenger space, therefore, the change of complex stiffness of the frame bushes is more efficient than modification of other parts of the vehicle such as body, frame and suspension. The purpose of this study is to reduce the vibration level for ride comfort by optimization of complex stiffness of frame bushes. In order to do this end, simple finite element vehicle model was constructed and the complex stiffness of frame bushes was set to be design variable. Objective function was defined to reflect passenger ride comfort and genetic algorithm and sub-structure synthesis were applied for minimization of the objective function.

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Phosphorescent Azacrown Ether-appended Iridium (III) Complex for the Selective Detection of Hg2+ in Aqueous Acetonitrile

  • Li, Yinan;Yoon, Ung-Chan;Hyun, Myung-Ho
    • Bulletin of the Korean Chemical Society
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    • 제32권1호
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    • pp.122-126
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    • 2011
  • A new phosphorescent cyclometalated heteroleptic iridium (III) complex with an ancillary ligand of 4-azacrownpicolinate was prepared and its metal ion selective phosphorescent chemosensing behavior was investigated. The new iridium (III) complex exhibits notable phosphorescence quenching for Hg2+ in aqueous 50% acetonitrile solution with respect to the selective phosphorescent detection of various metal ions including $Li^+,Na^+,K^+,Cs^+,Mg^{2+},Ca^{2+},Ba^{2+},Fe^{2+},Ni^{2+},Cu^{2+},Zn^{2+},Ag^+,Pb^{2+},Cd^{2+},Cr^{2+},Cr^{3+}$ and $Hg^{2+}$. The phosphorescence quenching for $Hg^{2+}$ increased linearly with increasing concentration of $Hg^{2+}$ in the range of $10{\mu}M-700{\mu}M$ even in the presence of other metal ions, except for $Cu^{2+}$. Consequently, the new iridium (III) complex has the potential to be utilized for the determination of parts per million levels of $Hg^{2+}$ in aqueous acetonitrile media.

A force-Guided Control with Adaptive Accommodation Bor Complex Assembly

  • Sungchul Kang;Kim, Munsang;Lee, Chong W.;Lee, Kyo-Il
    • 제어로봇시스템학회:학술대회논문집
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    • 제어로봇시스템학회 1998년도 제13차 학술회의논문집
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    • pp.14-19
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    • 1998
  • In this paper, a target approachable force-guided control with adaptive accommodation for the complex assembly is presented. The complex assembly (CA) is defined as a task which deals with complex shaped parts including concavity or whose environment is so complex that unexpected contacts occur frequently during insertion. CA tasks are encountered frequently in the field of the manufacturing automation and various robot applications. To make CA successful, both the bounded wrench condition and the target approachability condition should be satisfied simultaneously during insertion. By applying the convex optimization technique, an optimum target approaching twist can be determined at each instantaneous contact state as a global minimum solution. Incorporated with an admissible perturbation method, a new CA algorithm using only the sensed resultant wrench and the target twist is developed without motion planning nor contact analysis which requires the geometry of the part and the environment. Finally, a VME-bus based real-time control system is built to experiment various CA task. T-insertion task as a planar CA and double-peg assembly task as a spacial assembly were successfully executed by implementing the new force-guided control with adaptive accommodation.

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프레임 차량의 주행 진동 저감을 위한 프레임 부시 복소동강성계수 크기 결정에 관한 연구 (A Study on Determination of Complex Stiffness of Frame Bush for Ride-comfort Improvement of Body-on-frame Vehicle)

  • 정면규;김기선;김광준
    • 한국소음진동공학회논문집
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    • 제16권6호
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    • pp.619-626
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    • 2006
  • Body-on-frame type vehicle has a set of frame bushes between body and frame for vibration isolation. Such frame bushes are important vibration transmission paths to passenger space for excitations during driving. In order to reduce the vibration level of passenger space, therefore, change of complex stiffness of the frame bushes is more efficient than modification of other parts of the vehicle such as body, frame and suspension. The purpose of this study is to reduce the vibration level for ride comfort by optimization of complex stiffness of frame bushes. In order to do this, a simple finite element vehicle model was constructed and complex stiffness of the frame bushes was set to be design variables. The objective function was defined to reflect frequency dependence of passenger ride comfort. Genetic algorithm and sub-structure synthesis were applied for minimization of the objective function. After optimization level at a position of interest on the car body was reduced by about 43.7 % in RMS value. Causes for optimization results are discussed.

객관적으로 정량화된 복합 신호음의 조화도 (Objectively Quantified Consonance of Complex Sounds)

  • 전상배;최인용;이민구;성굉모
    • 한국음향학회지
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    • 제26권7호
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    • pp.323-327
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    • 2007
  • 본 논문에서는 객관적으로 정량화된 복합 신호음의 조화도를 새로운 심리 음향 파라미터로 제안하였다. 사람이 복합신호음을 인지하는 과정에서 발생하는 masking 효과, 등청감 곡선, criticalband 등의 심리음향학적인 모델들을 적용시킨 후, 그 소리가 어느정도의 조화도를 갖는지를 정량화시키는 모델을 제안하였고, 이를 검증하기 위하여 복합음으로 구성된 자동차 Horn 신호로 실험을 수행하였다. 실험 결과, 제안한 알고리즘에 의하여 정량화된 객관적인 조화도와 청취 평가를 통한 주관적인 조화도가 0.95의 cross correlation을 보였다. 현재 객관적인 심리음향학적인 파라미터로는 Zwicker 파라미터 외에는 거의 전무한 상태여서 제안하는 알고리즘을 통하여 소리의 심리음향학적인 효과를 보다 객관적으로 파악하는 데에 도움이 될 것으로 보인다.

토양내 중금속 존재형태와 미나리중 함량과의 관계 (Relationships between Speciation of Heavy Metals in Soil and Water Dropwort (Oenanthe javanica DC.) Cultivated near Industrial Complex)

  • 정구복;김원일;이종식;김진호;이정택
    • 한국토양비료학회지
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    • 제40권2호
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    • pp.164-171
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    • 2007
  • 공단인근의 여러 중금속이 복합적으로 오염된 토양에서 중금속의 존재형태와 미나리 중 함량과의 관계를 평가하기 위하여 미나리 재배토양, 농수로 퇴적 저니토 및 대조토양과 동일지점에서의 미나리를 채취하여 분석 검토하였다. 토양의 중금속 총함량 중 Cd, Cu 및 Ni의 평균농도가 Kloke (1979)가 제안한 중금속의 허용한계치를 초과하였다. 중금속별 토양 내 주된 존재형태는 Cd이 치환태였고, 다른 중금속 (Cu, Zn, Ni 및 Pb)은 Fe-Mn 산화물 및 잔류 형태로 나타났다. 재배토양과 농수로 저니토의 형태별 함량에 의하여 환산된 잠재적인 중금속 이동계수는 Cd>Zn>Ni>Cu>Pb 순이였고, 특히 Cd의 경우 대조토양에 비하여 매우 높은 것으로 알수 있었다. 토양의 Cd 전함량과 토양 내 이동성이 높은 치환성 및 Fe-Mn 산화물 분포비율과는 정의 상관, 이동성이 낮은 잔류태와는 부의 상관을 보였다. 미나리 부위별 중금속은 대부분이 뿌리에 축적되었으며, 지상부로의 이행성은 Cd과 Zn가 줄기에서 높았고, Cu와 Ni 함량은 오히려 잎에서 높았다. 토양 중금속 중 Cd, Cu 및 Ni의형태별 함량과 미나리 중 함량과 관련성이 높았고, 특히 치환성 Cd과 Ni 함량은 미나리 중 함량과 고도의 정의상관을 보였다.