• 산업경영시스템학회지
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• 제35권1호
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• pp.39-46
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• 2012

An unmanned aerial vehicle (UAV) is a powered aerial vehicle that does not carry a human operator, uses aerodynamic forces to provide vehicle lift, can fly autonomously or be piloted remotely, can be expendable or recoverable, and can carry a lethal or non-lethal payload. An UAV is very important weapon system and is currently being employed in many military missions (surveillance, reconnaissance, communication relay, targeting, strike, etc.) in the war. To accomplish UAV's missions, guarantee of survivability should be preceded. The main objective of this study is a local path planning to maximize survivability for UAV on the battlefield of dynamic threats (obstacles, surface-to-air missiles, radar etc.). A local path planning is capable of producing a new path in response to environmental changes. This study suggests a $Smart$ $A^*$ (Smart A-star) algorithm for local path planning. The local path planned by $Smart$ $A^*$ algorithm is compared with the results of existing algorithms ($A^*$ $Replanner$, $D^*$) and evaluated performance of $Smart$ $A^*$ algorithm. The result of suggested algorithm gives the better solutions when compared with existing algorithms.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 2005년도 ICCAS
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• pp.580-585
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• 2005

A QRT(Quad-Rotor Type) hovering robot system is developed for quick detection and observation of the circumstances under calamity environment such as indoor fire spots. The UAV(Unmanned Aerial Vehicle) is equipped with four propellers driven by each electric motor, an embedded controller using a DSP, INS(Inertial Navigation System) using 3-axis rate gyros, a CCD camera with wireless communication transmitter for observation, and an ultrasonic range sensor for height control. The developed hovering robot shows stable flying performances under the adoption of RIC(Robust Internal-loop Compensator) based disturbance compensation and the vision based localization method. The UAV can also avoid obstacles using eight IR and four ultrasonic range sensors. The VTOL(Vertical Take-Off and Landing) flying object flies into indoor fire spots and sends the images captured by the CCD camera to the operator. This kind of small-sized UAV can be widely used in various calamity observation fields without danger of human beings under harmful environment.

• 한국전자통신학회논문지
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• 제10권6호
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• pp.721-728
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• 2015

사람 중심이었던 인터넷이 사물 인터넷으로 진화함에 따라 우리들의 삶이 보다 스마트하게 발전하고 있다. 사물 인터넷(IoT)은 물리적 객체나 전자 제품, 소프트웨어, 센서 및 제조업체, 운영자 또는 연결된 다른 장치와 데이터를 교환하여 더 큰 가치와 서비스를 달성 할 수 있도록 연결된 사물 네트워크를 말한다. 지금까지 계량 정보 분석과 미래 유망영역 탐지에 대한 연구는 키워드를 중심으로 수행해왔다. 본 논문에서는 문헌에서 키워드 매핑에 대한 동태적 분석을 통하여 최근에 관심 영역인 사물 인터넷과 스마트 디바이스에 대한 미래 유망 영역을 탐지하는 방법을 제시한다.

• 한국환경과학회지
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• 제25권4호
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• pp.525-534
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• 2016

The biological wastewater treatment plant, which uses microbial community to remove organic matter and nutrients in wastewater, is known as its nonlinear behavior and uncertainty to operate. Therefore, operation of the biological wastewater treatment process much depends on observation and knowledge of operators. The manual inspection of human operators is essential to manage the process properly, however, it is impossible to detect a fault promptly so that the process can be exposed to improper condition not securing safe effluent quality. Among various process faults, equipment malfunction is critical to maintain normal operational state. To detect equipment faults automatically, the dynamic time warping was tested using on-line oxidation-reduction potential (ORP) and dissolved oxygen (DO) profiles in a sequencing batch reactor (SBR), which is a type of wastewater treatment process. After one cycle profiles of ORP and DO were measured and stored, they were warped to the template profiles which were prepared already and the distance result, accumulated distance (D) values were calculated. If the D values were increased significantly, some kinds of faults could be detected and an alarm could be sent to the operator. By this way, it seems to be possible to make an early detecting of process faults.

• 제어로봇시스템학회논문지
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• 제11권7호
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• pp.602-608
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• 2005

In the virtual environment, force feedback to the human operator makes virtual experiences more realistic. To ensure the safe operation and enhance the haptic feeling, stability should be guaranteed. Both motors and brakes are commonly used for haptic devices. Motors can generate a torque in any direction, but they can make the system active during operation, thus leading to instability. Brakes can generate a torque only against their rotation, but they dissipate energy during operation, which makes the system intrinsically stable. Consequently, motors and brakes are complementing each other. In this research, a two degree-of-freedom (DOF) haptic device equipped with motors and brakes has been developed to provide better haptic effects. Each DOF is actuated by a pair of motor and brake. Modeling of the environment and the control method are needed to utilize both actuators. Among various haptic effects, contact with the virtual wall, representation of friction and representation of plastic deformation have been investigated extensively in this paper. It is shown that the hybrid haptic device is more suited to some applications than the motor-based haptic device.

• 한국정밀공학회지
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• 제12권8호
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• pp.53-62
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• 1995

In recent years, the rapid development of the machine tool and tough insert has made metal removal rates increase, and automatic system without human supervision requires a higher degree reliability of machining process. Therefore the control of chips is one of the important topics which deserves much attention. The chip classification was made based upon standard deviation of the mean cutting force measured by a tool dynamometer. STS304was chosen as the workpiece which is known as the difficult-to-cut material and mainly saw-toothed chip produced, and the chip type according to the standard deviation of mean cutting force was classified into five categories in this experiment. Long continuous type chip which interrupts the normal cutting process, and damages the operator, tool and workpiece has low standard deviation value, while short broken type chip, which is favourable chip for disposal, has relatively large standard deviation value. In addition, we investigated the possibility that the chip type can be predicted analyzing the relationship between chip type and cutting condition by the trained neural network, and obtained favourable results by which the chip type can be predicted with cutting conditon before cutting process.

• 화약ㆍ발파
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• 제23권1호
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• pp.1-8
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• 2005

화학류발파작업 가운데 장약, 전색, 결선작업은 많은 힘과 시간이 소요되어 작업자세에 따른 직업자의 불편도와 근부담이 증가하게 된다. 따라서 작업상 인적오류를 유발할 가능성이 높아진다. 이러한 원인은 작업자로 하여금 중요한 작업을 누락시키거나 근도반응을 일으켜 결국 사고와 재해로 연결되므로 이에 대한 체계적 연구가 요구된다. 화약발파작업에서 자세의 변화에 따라 발생할 수 있는 위험요인분석에는 OWAS, RULA, REBA, OSHA, JSI, NLE, TVAV, BLUE-X가 있으나 본 연구에서는 OWAS, RULA, REBA기법으로 평가하고 분석하였다. 그 결과 근골격계질환과 2차사고의 발생개연성이 큰 것으로 분석되었다.

• 농촌지도와개발
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• 제22권1호
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• pp.15-24
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• 2015

Responsible tourism attracting worldwide attention has supported local economy and community development as a type of alternative tourism. This study explored the perception toward fairness in tourism and operation status of responsible tour operators in South Korea by conducting in-depth interviews with probe questions. Ten responsible tour operators were interviewed with a semi-structured interview questionnaire for one upto two hours. From the interview data, six themes were identified as difficulties of responsible tour operators: lack of manpower, advertising and promotion, absence of marketing strategy, regulation, lack of budget and lack of recognition of responsible tourism. As government support identified through the interviews, there are the followings seven themes: a low entry barrier market, investment in human resources, resource utilization, community-based policies, connection with local produce, community support and connection system of responsible travel agencies with intermediate support organizations at a local level, The findings of this paper implicate the underlying subject of responsible tourism from a tour operators' perspective.

• Journal of Mechanical Science and Technology
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• 제15권1호
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• pp.1-9
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• 2001

The recent spread of scaled telemanipulation into microsurgery and the nano-world increasingly requires the identification of the possible operation region as a main system specification. A teleoperation system is a complex cascaded system since the human operator, master, slave, and communication are involved bilaterally. Hence, a small time delay inside a master and slave system can be critical to the overall system stability even without communication time delay. In this paper we derive an upper bound of the scaling product of position and force by using Llewellyns unconditional stability. This bound can be used for checking the validity of the designed bilateral controller. Time delay from the sample and hold of computer control and its effects on stability of scaled teleoperation are modeled and simulated based on the transfer function of the teleoperation system. The feasible operation region in terms of position and force scaling decreases sharply as the sampling rate decreases and time delays inside the master and slave increase.

• 대한의용생체공학회:의공학회지
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• 제15권4호
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• pp.447-454
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• 1994

기하학적인 모델을 이용한 좌심실에 대한 단축 2D 심초음파도에서의 심내벽 윤관석의 완전 자동검출방법을 제안하였다. 이 방법은 3단계의 과정에 걸쳐 수행된다. 첫번째 단계는 부표본화된 영상에 초기 중심 추정 알고리듬을 적용하여 초기 중심을 추정한다. 두번째 단계에서는 원 영상에 중심추성 알고리듬을 적용하여 정확한 중심과 타원추정에 필요한 정보를 구한다음, 심내벽에 근사하는 타원모델을 추정한다. 세번째 단계는 추정한 타원모델에 근거한 코스트 함수로서 심내벽 윤관석을 검출한다. 제안된 방법을 조작자의 수동적인 개입없이도 효과적인 결과를 보여준다.