• IE interfaces
• /
• v.3 no.2
• /
• pp.39-51
• /
• 1990

One of the most important and powerful tools available for design and/or study of the operation of complex systems and processes is simulation. Since automated material handling systems like AS/RS are often quite complex, a network-based simulation model is developed to analyze an automobile part supplier's automated storage and retrieval system(AS/RS). The network simulation model is implemented in the SLAM Ⅱ on a VAX 8800 computer. Performance of the AS/RS was tested for 3 dispatching rules, 3 work load levels, 2 storage policies, 3 levels of stacker crane break-down, and 2 conveyor system layouts. Results indicate that the AS/RS performance is primarily affected by the dispatching rule and work load level.

• Ocean and Polar Research
• /
• v.25 no.4
• /
• pp.633-644
• /
• 2003

The distribution and abundance of Antarctic krill (Euphausia superba), particularly in the South Atlantic, has traditionally been viewed as primarily determined by the flow of the Antarctic Circumpolar Current. Krill are viewed as being particles on a conveyor belt that carries them around the Antarctic continent resulting in a single circumpolar population. The evidence to support this viewpoint is largely circumstantial and there is very little direct evidence available of krill being moved by the currents-krill flux. There is also considerable biological and physical evidence which suggests that other factors may play a dominant role in the life history and distribution of krill. This review examines the evidence fur krill flux and also examines evidence that does not accord with this theory. The management implications of assuming krill flux are outlined and some lines for future research are suggested.

• Korean Journal of Computational Design and Engineering
• /
• v.10 no.3
• /
• pp.199-209
• /
• 2005

In this paper, a digital simulation model for an automotive assembly line is constructed by adapting a digital manufacturing methodology. Applied methodology is a simulation for a plant level of the assembly production line. The first significance of this methodology is a validation of the production planning based on various scenarios. The second is pre-verification for the new production plan or production method. The third is a visualization of the production process. Several models were implemented and those models were verified. Then, it was possible to find a most efficient production scenario and production method.

• Proceedings of the Korea Information Processing Society Conference
• /
• 2003.11b
• /
• pp.643-646
• /
• 2003

이 논문은 작업 대상물(object)을 최소 시간으로 interception 하기 위한 방법에 대하여 기술한다. 목표는 로봇이 world coordinate system을 기준으로 x축으로 이동하는 컨베이어 라인 상에서 이동되는 작업 대상물을 intercept 하는 것이다. 컨베이어 시스템이 최소의 시간으로 작업 대상물을 intercept하기 위해서는 다음의 주요 계획이 필요하다. 첫째는 최적의 object과 end effector의 meeting point 선택, 두 번째는 첫 번째 계획이 실효를 이루기 위한 로봇의 trajectory선택이다. 두 가지의 계획 중 여기서는 두 번째 계획이 최적이라고 가정하고 첫 번째 계획법 즉, 컨베이어 시스템 로봇을 이용한 작업 대상물의 gripping 동작을 행함에 있어서 최소 시간으로 작업대상물을 gripping 하기 위한 컨베이어 시스템과 minimum time gripping 알고리즘이 제시된다.

• Proceedings of the Korean Society for Agricultural Machinery Conference
• /
• 2000.11b
• /
• pp.354-362
• /
• 2000

In Korea, researches on year-round leaf vegetables production system are in progress, most of them focused on environmental control. Therefore, automation technologies for harvesting, transporting, and grading are in great demand. A robot system for harvesting lettuces, composed of a 3-DOF (degree of freedom) manipulator, an end-effector, a lettuce feeding conveyor, an air blower, a machine vision system, six photoelectric sensors, and a fuzzy logic controller, was developed. A fuzzy logic control was applied to determine appropriate grip force on lettuce. Leaf area index and height were used as input variables and voltage as an output variable for the fuzzy logic controller. Success rate of the lettuce harvesting was 94.12%, and average harvesting time was approximately 5 seconds per lettuce.

• Journal of Biosystems Engineering
• /
• v.25 no.1
• /
• pp.63-70
• /
• 2000

In Korea, researches for year-round leaf vegetables production system are in progress and the most of them are focused on environment control. Automation technologies for harvesting , transporting and grading need to be developed. This study was conducted to develop harvesting process automation system profitable to a competitive price. 1. Manipulator and end-effector are to be designed and fabricated , and fuzzy logic controller for controlling these are to be composed. 2. The entire system constructed is to be evaluated through a performance test. A robot system for harvesting a lettuce was developed. It was composed of a manipulator with 20DOF (degrees of freedom) an end-effector, a lettuce feeding conveyor , an air blower , a machine vision device, 6 photoelectric sensors and a fuzzy logic controller. A fuzzy logic control was applied to determined appropriate grip force on lettuce. Leaf area index and height index were used as input parameters, and voltage was used as output parameter for the fuzzy logic controller . Success rate of the lettuce harvesting system was 93.06% , and average harvesting time was about 5 seconds per lettuce.

• Journal of Biosystems Engineering
• /
• v.23 no.6
• /
• pp.629-634
• /
• 1998

Factory-style plant production system aims to produce the standardized horticultural products with high quality and cleanness. In Korea, researches for year-round leaf vegetables production system are in progress and the most of them are focused on environment control. Automating technologies for harvesting, transporting and grading need to be developed. A lettuce harvesting system applicable to the plant factory was studied. It was composed of an articulated robot with a cutter and a gripper, lettuce feeding conveyor and air blower. Success rate of the developed system was 94.7 %. The system carried out harvesting a lettuce smoothly and the harvesting time was about 6 seconds per lettuce. The results showed a feasibility of robotic lettuce harvesting.

• Proceedings of the Korean Society for Quality Management Conference
• /
• 2009.10a
• /
• pp.131-135
• /
• 2009

This paper considers the sequencing of products in car assembly lines. The sequence which minimizes overall utility work in car assembly lines reduce the cycle time and the risk of conveyor stopping. The sequencing problem is solved using Tabu Search. Tabu Search is a heuristic method which can provide a near optimal solution in real time. The performance of proposed technique is compared with existing heuristic methods in terms of solution quality and computation time. Various examples are presented and experimental results are reported to demonstrate the efficiency of the technique.

• Journal of Welding and Joining
• /
• v.19 no.2
• /
• pp.176-181
• /
• 2001

Reflow soldering characteristics of Sn-3.5Ag and Sn-37Pb balls for BGA(Ball grid Array) were investigated. Diameter of 0.76mm ball was set on a Cu/Ni/Au-coated pad and reflowed in air with changing peak soldering temperature and conveyor speed. Peak temperatures were changed from 240 to 28$0^{\circ}C$ for Sn-3.5Ag, and from 220 to 26$0^{\circ}C$ for Sn-37Pb balls. As results, heights of solder balls increased and widths decreased with peak soldering temperature. Through aging treatment at 10$0^{\circ}C$ for 1.000 hrs, average hardness of Sn-3.5Ag balls bonded at 25$0^{\circ}C$ cecreased from 14.90Hv to 12.83Hv And with same aging conditions, average shear strength of Sn-3.5Ag balls bonded at 26$0^{\circ}C$ decreased from 1727gf to 1650gf.

• Transactions of the Korean Society of Mechanical Engineers A
• /
• v.32 no.10
• /
• pp.897-904
• /
• 2008

Egg grading machine is used in poultry raising industry to classify eggs by their weight and to pack up them. Packer holder mechanism is a main part of the egg grading machine, of which role is to take eggs fallen from conveyor belt, and afterward to transfer eggs vertically to mold tray. The vertical motion of packer holder is usually driven by slider-crank mechanism or cam. This paper describes development of the cam in packer holder based on kinematic analysis of packer holder mechanism and measurement of acceleration and noise of the cam to verify performance of it. Several cams that are designed and manufactured by the author of this paper according to different design specification are compared to determine the best solution for egg transfer in the packer holder mechanism.