• Explosives and Blasting
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• v.36 no.1
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• pp.1-11
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• 2018

In this study, several underwater steel cutting tests and AUTODYN numerical analyses were conducted to evaluate the penetration performance of a shaped charge device. Parameter analyses for the contribution rate were conducted by using the robust design method. The parameters adopted in this study were chamber type, stand-off, and wire setting, each of which had three levels in the analysis. Analysis results showed that the contribution rate was most affected by the stand-off, followed by the chamber type and wire setting. Experiments of underwater steel cutting were conducted at water depth of 25m. As expected, the experiments and numerical simulation showed similar results for underwater steel cutting performance, and thus the feasibility of the shaped charge device for underwater steel cutting at deep water depth was verified.

• Journal of the Institute of Electronics Engineers of Korea SD
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• v.48 no.7
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• pp.76-81
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• 2011

A new via cutting structure in 2-layer DRAM package substrate has been fabricated to lower its power distribution network(PDN) impedance. In new structure, part of the via is cut off vertically and its remaining part is designed to connect directly with the bonding pad on the package substrate. These via structure and substrate design not only provide high routing density but also improve the PDN impedance by shortening effectively the path from bonding pad to VSSQ plane. An additional process is not necessary to fabricate the via cutting structure because its structure is completed at the same time during a process of window area formation. Also, burr occurrence is minimized by filling the via-hole inside with a solder resist. 3-dimensional electromagnetic field simulation and S-parameter measurement are carried out in order to validate the effects of via cutting structure and VDDQ/VSSQ placement on the PDN impedance. New DRAM package substrate has a superior PDN impedance with a wide frequency range. This result shows that via cutting structure and power/ground placement are effective in reducing the PDN impedance.

• Journal of the Korea Society of Computer and Information
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• v.9 no.4 s.32
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• pp.109-116
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• 2004

This paper describes a cloth simulation system for dressing 3D virtual human model with different pieces of clothing. The garments are constructed of cutting patterns seamed together. The system reads a body file and a cutting pattern file and produces a new model dressed with the specified garment by using a physical simulation based on a mass-spring model. For the realistic cloth simulation, it performs collision detection and response between triangles of the 3D human model and the garment. Because the number of triangles of a human model is very large. the collision detection and response requires a lot of time. To overcome this problem, we propose a pruning method which decreases the number of collision detection and response by a space-subdivision method. Experimental results show that the system produces realistic images and makes it possible to sew a garment around a virtual human body in several seconds.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.16 no.1
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• pp.118-123
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• 2017

It is well known that water jetting is now widely used in the advanced cutting processes of polymers, metals, glass, ceramics, and composite materials because of some advantages, such as heatless and non-contacting cutting different from the laser beam machining. In this paper, we proposed the simulation model of waterjet by lengths and the inner spiral structure of the nozzle. The simulation results show that the outlet velocity of the nozzle is faster than the inlet. Furthermore, we found rapid velocity reduction after passing through the outlet. The nozzle of diameter ${\phi}500$ and length 70mm, shows the optimal fluid width and velocity distribution. Also, the nozzle with inner spiral structure shows a Gaussian distribution of velocity and this model is almost twice as fast as the model without spiral structure, within the effective standoff distance (2.5 mm). In the future, when inserting abrasive material into the waterjet, we plan to analyze the fluid flow and the particle behavior through a simulation model.

• Journal of the Korea Society for Simulation
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• v.8 no.2
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• pp.87-100
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• 1999

A manufacturing environment without a computerized system causes numerous problems, since many important decisions are made based on the experience of veteran staffs. Especially, when a strategy for the improvement of manufacturing efficiency is considered, it is hard to predict the effect of the strategy. A solution to the problem without large investment of the computerized system is the simulation study. This paper shows the modeling and simulation based on DEVS(Discrete Event System Specification). Two types of models are implemented, one for representing the current production strategy and the other for the new strategy. The new strategy is expressed as priority rules within the model. The process in concern is the metal grating production process in which the size of the group, for applying a specific cutting and scheduling strategies, is one of the important factors in improving the production efficiency. Some reliable criteria for the evaluation related to the production effeciency are established from the simulation study.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.20 no.11
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• pp.30-35
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• 2021

In this study, a machine simulation system was built using the actual scale of an AC-type 5-axis machine tool for mold surface machining that can be used in applications, such as, modeling and machine building, stroke, and collision detection. The validity of the 5-axis machine simulation system was verified by performing tool path generation, post-processing, machine simulation, prototype motion simulation, and an actual cutting experiment. This entire process was intended to activate the 5-axis machining in mold surface machining.

• Journal of the Korea Institute of Military Science and Technology
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• v.11 no.2
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• pp.80-87
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• 2008

The LVC(Live, Virtual, Constructive) system of CTC(Combat Training Center) is at the very cutting edge of modeling and simulation technology, which has become widely accepted an enabler for a new military training transformation. In this paper, the architecture of LVC system is proposed for the Korean brigade-level CTC, and high level operational architecture, system architecture, and technical standard architecture are suggested.

• Journal of KIISE:Information Networking
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• v.35 no.6
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• pp.497-509
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• 2008

Various algorithms and architectures for efficient packet classification have been widely studied. Packet classification algorithms based on a decision tree structure such as HiCuts and HyperCuts are known to be the best by exploiting the geometrical representation of rules in a classifier. However, the algorithms are not practical since they involve complicated heuristics in selecting a dimension of cuts and determining the number of cuts at each node of the decision tree. Moreover, the cutting is not efficient enough since the cutting is based on regular interval which is not related to the actual range that each rule covers. In this paper, we proposed a new efficient packet classification algorithm using a range cutting. The proposed algorithm primarily finds out the ranges that each rule covers in 2-dimensional prefix plane and performs cutting according to the ranges. Hence, the proposed algorithm constructs a very efficient decision tree. The cutting applied to each node of the decision tree is optimal and deterministic not involving the complicated heuristics. Simulation results for rule sets generated using class-bench databases show that the proposed algorithm has better performance in average search speed and consumes up to 3-300 times less memory space compared with previous cutting algorithms.

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.26 no.1
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• pp.35-40
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• 2016

End milling process is one of the broadly used manufacturing process for precision machined parts and products. Machining performance is often limited by chatter vibration at the tool-workpiece interface. Chatter vibration is a type of machining self-excited vibration which originated from the variation in cutting forces and the flexibility of the machine tool structure. Even though lots of cutting tooling methods are developed and used in machining process, precise analysis of cutting tooling effect in view of chatter vibration behavior. This study presents numerical and experimental approaches to verify and effects of various cutting parameters to affect to chatter vibration stability. Acquired knowledge from this study will apply the optimal cutting conditions to improve a machining process.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.41 no.5
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• pp.353-359
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• 2017

The classical computer numerical control (CNC) machine is widely used for mold making in various industries. However, while improving the process, it has a negative effect on production quality and worker safety. As a result, the complaints of workers have increased and production quality has decreased. Therefore, we found optimizing cutting conditions to mold industrials for cutting conditions commonly used. However, the problem is the insert tool geometric modeling. In this study, the modeling of an insert tool was performed using the Solidworks program. The insert tool model was imported into the analysis application AdvantEdge, which predicted cutting forces, tool stress, and temperature.