• Journal of Institute of Control, Robotics and Systems
• /
• v.8 no.6
• /
• pp.514-523
• /
• 2002

Feeder arrangement is an important element of process planning for printed circuit board assembly systems. This paper newly proposes a feeder arrangement method for multihead-gantry chip mounters. The multihead-gantry chip mounters are very popular in printed circuit board assembly system, but the research has been mainly focused on single-head-gantry chip mounters. We present an integer programming formulation for optimization problem of multihead-gantry chip mounters, and propose a heuristic method to solve the large NP-complete problem in reasonable time. Dynamic programming method is then applied to feeder arrangement optimization to reduce the overall assembly time. Comparative simulation results are finally presented to verify the usefulness of the proposed method.

• Transactions of the Korean Society of Mechanical Engineers B
• /
• v.21 no.3
• /
• pp.405-413
• /
• 1997

A thermal optimization of the chip arrangement in the PCB channel oriented vertically and cooled by natural convection has been studied. The objective of this study is to find the chip arrangement that minimizes the maximum temperature of the entire PCB channel. SIMPLER algorithm is employed in the analysis, and the genetic algorithm is used for the optimization. The results show that the chip with a maximum volumetric heat generation rate has to be located at the bottom of the channel, and chips with relatively high heat generation rates should not be close to each other, and small chip should not be located between the large chips.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
• /
• 2001.07a
• /
• pp.757-760
• /
• 2001

We have used the random fluidic self-assembly (RFSA) technique based on the chip pattern of hydrophobic self-assembly layers to assemble microfabricated particles onto the chip pattern. Immobilization of DNA, fabrication of the particles and the chip pattern, arrangement of the particles on the chip pattern, and recognition of each using DNA fluorescence measurement were carried out. Establishing the walls, the arrangement stability of the particles was improved. Each DNA is able to distinguish by using the lithography process on the particles. Advantages of this method are process simplicity, wide applicability and stability. It is thought that this method can be applicable as a new fabrication technology to develop a minute integration type biosensor microarray.

• Journal of Institute of Control, Robotics and Systems
• /
• v.11 no.2
• /
• pp.144-151
• /
• 2005

We propose an optimization method to reduce the assembly time of chip mounters. Feeder arrangement and assembly sequence are determined considering the multiple feeder assignment. The problem is divided into two sub-problems: feeder arrangement problem and assembly sequence problem. We present mathematical model for each sub-problem. The clustering algorithm and assignment algorithm are applied to solve the feeder arrangement problem. The assignment algorithm and connection algorithm are applied to solve the assembly sequence problem. Simulation results are then presented to verity the usefulness of the proposed method.

• Proceedings of the KIEE Conference
• /
• 2002.11a
• /
• pp.263-265
• /
• 2002

We have used the secondary-step immobilization methods based on the chip pattern of hydrophobic self-assembly layers to assemble microfabricated particles onto the chip pattern. Immobilization of DNA, fabrication of the particles and the chip pattern, arrangement of the particles on the chip pattern, and recognition of each using DNA fluorescence measurement were carried out. Establishing the walls, the arrangement stability of the particles was improved. Each DNA is able to distinguish by using the lithography process on the particles. Advantages of this method are process simplicity, wide applicability and stability. It is thought that this method can be applicable as a new fabrication technology to develop a minute integration type biosensor microarray.

• The Transactions of the Korean Institute of Electrical Engineers C
• /
• v.51 no.7
• /
• pp.328-334
• /
• 2002

The DNA chips are devices associating the specific recognition properties of two DNA single strands through hybridization process with the performances of the microtechnology. In the literature, the "Gene chip" or "DNA chip" terminology is employed in a wide way and includes macroarrays and microarrays. Standard definitions are not yet clearly exposed. Generally, the difference between macro and microarray concerns the number of active areas and their size, Macroarrays correspond to devices containing some tens spots of 500$\mu$m or larger in diameter. microarrays concern devices containing thousnads spots of size less than 500$\mu$m. The key technical parameters for evaluating microarray-manufacturing technologies include microarray density and design, biochemical composition and versatility, repreducibility, throughput, quality, cost and ease of prototyping. Here we report, a new method in which minute particles are arranged in a random fashion on a chip pattern using random fluidic self-assembly (RFSA) method by hydrophobic interaction. We intend to improve the stability of the particles at the time of arrangement by establishing a wall on the chip pattern, besides distinction of an individual particle is enabled by giving a tag structure. This study demonstrates the fabrication of a chip pattern, immobilization of DNA to the particles and arrangement of the minute particle groups on the chip pattern by hydrophobic interaction.ophobic interaction.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
• /
• v.28 no.10
• /
• pp.676-681
• /
• 2015

Recently many studies being carried out to increase the light efficiency of LED. The external quantum efficiency of LED, generally the light efficiency, is determined by the internal quantum efficiency and the light extraction efficiency. The internal quantum efficiency of LED was already reached to more than 90%, but the light extraction efficiency is still insufficient compared with the internal quantum efficiency because the total internal reflection is generated in the interface between the LED chip and air. Thus, we studied about flip chip LED with PSS and performed the optical simulation which find more optimized PSS for flip chip LED to increase the light extraction efficiency. Decreasing of the total internal reflection and effect of diffused reflection according to PSS improved the light extraction efficiency. To get more higher the efficiency, we simulated flip chip with PSS that the parameters are arrangement, edge spacing, radius, height and shape of PSS.

• The Research Journal of the Costume Culture
• /
• v.20 no.6
• /
• pp.869-882
• /
• 2012

The purpose of this study is to obtain the patent for extracting the color map and color chip from the color image source and to develop color image map for fashion design. For this study, fashion image maps were produced from 210 pictures with Adobe Photoshop CS2 program targeting 200 university students from 2004 to 2006. The procedures for extracting the color map and color chip included providing the color image, the filtering phase, the segmentation phase, the extraction phrase, and the arrangement phase. Based on the results of this study, patent application was made to KIPO(Korean Intellectual Property Office) for this invention. The following effects can be expected from the standpoint of design based on the case study. First, it is a straight forward procedure to extract a color chip and color map from a color image. Second, it can be applied to various art works based on the recombination of colors as representative colors can be extracted from the related color image that combines a variety of colors. Third, desired colors can be selected based on the taste cluster classification or sensibility axis of design by extracting the representative color from the color image.

• 한국정보디스플레이학회:학술대회논문집
• /
• 2009.10a
• /
• pp.1272-1273
• /
• 2009

We demonstrate conformal phosphor coating and patterning methods on light emitting diodes (LEDs) using image processing based optofluidic maskless lithography (IP-OFML) system in microfluidic channels. IP-OFML allows a real-time detection and dynamic mask generation for packaging of randomly dispersed microchips. Our system detects each chip by considering rotation of the chip through image processing regardless of their arrangement error. Therefore, it precisely packages the chip making conformal polymer layer.

• Proceedings of the KIEE Conference
• /
• 2002.11a
• /
• pp.197-199
• /
• 2002

This paper describes the effects of chip arrangement configurations and the dimension of a reflecting cup upon the light output characteristics of a white lamp composed of RGB LED chips. As a result of simulation, the shorter distance between adjacent chips leads to a relative decrease in the light output efficiency due to inter-chip absorption of quanta, but rather uniform color mixing is expected. Among the factors of designing a reflecting cup it is the tilt angle of the cup wall that plays a determining role upon the variation of the light distribution. The light distribution shows a sudden change of pattern from Lambertian to Batwing at about $35^{\circ}{\sim}40^{\circ}$ of tilt angle in case of a silver-coated wall cup.