• Journal of the Korea Academia-Industrial cooperation Society
• /
• v.10 no.9
• /
• pp.2202-2209
• /
• 2009

Joint paths are induced mathematically for many kinds of joint pattern between master- and sub-pipes. By compensating them with root gap of welds and kerf width, real cutting paths are determined. Their NC codes are generated, and the paths generated by NC code are verified by a ghost function. A beveling is implemented through tilting a torch in the A- and B-axis direction for 8 sections in the chuck rotation of C-axis. The effective CAM program was developed specially for 6-axis CNC pipe coasters which cut a master or sub- pipe along the cutting path and simultaneously fulfill a beveling process.

• KSII Transactions on Internet and Information Systems (TIIS)
• /
• v.8 no.2
• /
• pp.371-388
• /
• 2014

Cognitive Radio (CR) has been recently proposed as a promising technology to remedy the problems of spectrum scarcity and spectrum underutilization by enabling unlicensed users to opportunistically utilize temporally unused licensed spectrums in a cautious manner. In Cognitive Radio Ad Hoc Networks (CRAHNs), data routing is one of the most challenging tasks since the channel availability and node mobility are unpredictable. Moreover, the network performance is severely degraded due to large numbers of path failures. In this paper, we propose the Fault-Tolerant Cognitive Ad-hoc Routing Protocol (FTCARP) to provide fast and efficient route recovery in presence of path failures during data delivery in CRAHNs. The protocol exploits the joint path and spectrum diversity to offer reliable communication and efficient spectrum usage over the networks. In the proposed protocol, a backup path is utilized in case a failure occurs over a primary transmission route. Different cause of a path failure will be handled by different route recovery mechanism. The protocol performance is compared with that of the Dual Diversity Cognitive Ad-hoc Routing Protocol (D2CARP). The simulation results obviously prove that FTCARP outperforms D2CARP in terms of throughput, packet loss, end-to-end delay and jitter in the high path-failure rate CRAHNs.

• Journal of Korean Society of Industrial and Systems Engineering
• /
• v.35 no.1
• /
• pp.39-46
• /
• 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.

• Asian Journal of Business Environment
• /
• v.8 no.1
• /
• pp.7-15
• /
• 2018

Purpose -This paper is to study the process of the negative effects of Sino-foreign joint ventures, hoping to find out an effective path in which local enterprises can avoid the risks in the utilization of foreign capital, and ultimately achieve independent innovation. Research design, data, and methodology -The outflow of assets, the loss of local brands and the "technology hollowing-out" problem brought by joint ventures is becoming more and more serious. Based on conflict analysis graph model, this paper takes Yuhuan joint venture as an example to identify the conflict problem in Sino-foreign joint ventures. Results -The results of the stability analysis show that establishing joint venture cannot really realize the introduction of technology because the technology is fully controlled by the foreign part. So when introducing foreign capital, local enterprises should participate in R&D and master the initiative. Conclusions - Local enterprises should pay attention to patent containment and technology blockade of multinationals. Domestic enterprises should try to protect state-owned assets and local brands in Sino-foreign joint ventures. Independent innovation is the most effective strategy for the development of enterprises in China.

• Journal of the Korean Society of Industry Convergence
• /
• v.24 no.6_2
• /
• pp.883-890
• /
• 2021

In this study, joint analysis was conducted on the rock slope by aerial surveying using UAV. Aerial photos were taken using UAV to measure the directionality of the rock slope exposed to the site, and the directionality of the joint was analyzed using the photographed photos. UAV photography was taken under conditions of 90% overlap and an altitude of 50m. The photographing path was measured in the horizontal, vertical, and oblique directions based on the slope, and the joint characteristics were analyzed. Aerial surveying research on the joint directionality analysis of rock slopes is still incomplete, and the method for accurate joint directionality analysis is not presented strategically, so it is difficult to apply it in design. Through the results of this study, we would like to propose an flight photographing technique for the investigation of rock joints. As a result of the study, in the case of the joint investigation of the rock slope using UAV, it was necessary to change conditions such as altitude, aerial photography route, and overlap according to the size of the joint according to the site conditions.

• 제어로봇시스템학회:학술대회논문집
• /
• 1996.10a
• /
• pp.133-136
• /
• 1996

The nozzle dam task is essentially needed to maintain and repair nuclear power plants. For this task, an 8-dof redundant robot is studied with a local path-planning method[l] which is effective to find the optimal joint path in the constrained environment. In this paper, the method[l] is improved practically with the weight matrix and efficient algorithm to find working set. The effectiveness of the proposed method is demonstrated by simulation and animation.

• Transactions of the Korean Society of Automotive Engineers
• /
• v.4 no.3
• /
• pp.112-121
• /
• 1996

Applications of bonded dissimilar materials such as metal/ceramics and resin/metal joints, are very increasing in various industry fields. It is required to find crack propagation direction and path applying to the fracture mechanics on the bonded joint of dissimilar meterials. In this paper, crack propagation direction and path were simulated numerically by using boundary element method. Crack propagation angle is able to easily determine based on the maximum stress concept. Fracture tests of Al/Epoxy dissimilar materials with an interface crack are carried out under various mixed mode conditions by using the specimens of bonded scarf joints. It is found that the experimental results are well coincide with the analysis results of boundary element method.

• Journal of the Computational Structural Engineering Institute of Korea
• /
• v.12 no.2
• /
• pp.251-264
• /
• 1999

본 연구에서는 추계론적 동적시스템의 응답거동을 예측할 수 있는 반해석적 절차를 개발하였으며, 이를 이용하여 구분적선형시스템의 동적거동특성을 확률적 영역에서 분석하였다. 반 해석적 절차는 시스템의 추계론적 미분방정식에 상응하는 Fokker-Planck 방정식을 path-integral solotion을 이용하여 풂으로써 구할 수 있다. 결합확률밀도함수의 시간에 따른 전개과정을 통하여 시스템의 동적 응답거동 특성의 예측과 분석을 하고 시스템의 거동에 미치는 외부노이즈의 영향 또한 조사하였다. 반 해석적 방법은 위상면 상에서 결합확률밀도 함수를 통하여 응답거동의 예측은 물론 거동특성에 대하여 적절한 정보를 제공하는 것을 밝혔다. 혼돈거동의 특성은 외부노이즈가 존재하는 상황에서도 시스템의 응답 안에 잔재하는 것을 밝혔다.

• 제어로봇시스템학회:학술대회논문집
• /
• 1993.10a
• /
• pp.293-298
• /
• 1993

In this paper, methods for computing the time-optimal motion of a robotic manipulator are presented that considers the nonlinear manipulator dynamics, actuator constraints, joint limits, and obstacles. The optimization problem can be reduced to a search for the time-optimal path in the n-dimensional position space. These paths are further optimized with a local path optimization to yield a global optimal solution. Time-optimal motion of a robot with an articulated arm is presented as an example.

• Proceedings of the Korean Society of Precision Engineering Conference
• /
• 1996.04a
• /
• pp.383-387
• /
• 1996

This paper presents a steering control strategy applicable to vehicle path following problems. This control strategy is based on realistic nonlinear equations of motion of multibody systems described in terms of relative joint coordinates. The acceleration of the steering angle is selected as a control input of the system. This input is obtained by considering position and slope errors at current and at advance times. This steering control strategy is tested in circular and lane change maneuvers with a nonlinear vehicle model.