• Journal of the Korean Society of Manufacturing Process Engineers
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• v.18 no.7
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• pp.56-62
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• 2019

The high-precision laser scriber carries out scribing alumina ceramic substrates for manufacturing ultra-small chip resistors. The ceramic substrates are loaded, aligned, scribed, transferred, and unloaded. The entire process is fully automated, thereby minimizing the scribing cycle time of the ceramic substrates and improving the throughput. The scriber consists of the laser optical system, pick-up module of ceramic substrates, pre-alignment module, TH axis drive work table, automation module for substrate loading / unloading, and high-speed scribing control S/W. The loader / unloader unit, which has the greatest influence on the scribing cycle time of the substrates, carries the substrates to the work table that carries out the cutting line work by driving the X and Y axes as well as by adsorbing the ceramic substrates. The loader / unloader unit consists of the magazine up / down part, X-axis drive part for conveying the substrates to the left and right direction, and the vision part for detecting the edge of the substrate for the primary pre-alignment of the substrates. In this paper, the laser scribing machining simulation is performed by applying the instrument mechanism of each component module. Through this study, the scribing machining process is first verified by analyzing the process operation and work area of each module in advance. In addition, the scribing machining process is optimized by comparing and analyzing the scribing cycle time of one ceramic substrate according to the alignment stage module speed.

• Journal of Navigation and Port Research
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• v.32 no.1
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• pp.97-102
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• 2008

According to the trend of a large-sized vessel and a industrial carrier, the role of the independent contractors such as transport terminal operators, stevedores and warehousemen is increasing the base of cargo distribution that include the function of storage, warehousing, loading, unloading, trimming, dunnaging and lashing. But the common law doctrine of privity of contract has been a perennial source of difficulty for litigants seeking to enforce rights and obligations arising under a bill of lading contract. When carriage contract is negotiated, the concerned parties will be aware that some portion of obligations arising from the contract will be performed by the independent contractors engaged to carry out a particular function. It is reasonable for the independent contractors to be allowed the benefit of the carrier under the contract of carriage. As a part of the alleviating measures for the liability of independent contractors has been allowed various schemes, specially including 'Himalaya Clause'. Therefore, this study performed the validity of 'Himalaya Clause' by means of a recent judicial precedent by the Supreme Court and analyzed the rights of third parties, specially transport terminal operators, under the contract of carriage.

• Journal of Korea Multimedia Society
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• v.12 no.11
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• pp.1671-1679
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• 2009

The existing subjects of supply chain management, which link business firms to customers, have focused on forward logistics such as acquisition of low and subsidiary parts, manufacturing, distribution and sales. Consequently, it is emphasized that supply chain management has to be a sustainable business activity. Nevertheless, capabilities of reverse supply chain management for domestic companies are still relatively limited compared to advanced foreign companies. For this reason, this study aims to develop the service platform, which provides information on return, retrieval, abolish and recycling using RFID, includes information on packing, placement, loading and unloading and transportation of the goods. In order to achieve the purpose of this study, the research previous studies and analyze achieved diverse cases on reverse logistics, review the present state, and propose service platform application to manage reverse supply chain which will be applied.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.13 no.2
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• pp.253-265
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• 1993

This paper presents a numerical method for implementing a nonlinear constitutive material model developed by Lade, into a finite element computer program. The techniques used are based on the displacement method for the solution of axial symmetric and plane strain nonlinear boundary value problems. Laboratory behaviour of Baekma river sand(#40-60) is used to illustrate the determination of the parameters and verification of the model. Computer procedure is developed to determine the material parameters for the nonlinear model from the raw laboratory test data. The model is verified by comparing its predictions with observed data used for the determination of the parameters and then with observed data not used for the determination. Three categories of tests are carried out in the back-prediction exercise; (1) A hydrostatic test including loading and unloading response, (2) Conventional triaxial drained compression tests at three different confining pressure and (3) A model strip footing test not including in the evaluation of material parameters. Pertinent observations are discussed based on the comparison of predicted response and experimental data.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.34 no.11B
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• pp.1272-1282
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• 2009

This paper consists of two parts: the protocol for tag-to-tag mesh network and the implementation of dual-radio RFID system. Recently, RFID has been adopted in ports or warehouse, being attached to containers and palettes for loading/unloading automation. However, the RFID system has encountered one problem - some tags cannot receive any command from reader intermittently due to signal interference by containers or field equipments (e. g. cranes and yard tractors). This area where reader signal cannot reach is called dead-zone. The proposed method for solving the dead-zone problem is as follows. A zone which can be communicated directly between readers and tags communicates in 433MHz frequency band in compliance with ISO/IEC 18000-7 standard. On the other hand, dead-zone communicates in 2.4GHz frequency band by using tag-to-tag mesh network in compliance with IEEE 802.15.4 standard. The proposed method can not only save much cost to install additional readers but also help resolve the dead-zone problem. Furthermore, it can provide the easier, faster, and more economical network infrastructure.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.32 no.10
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• pp.831-835
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• 2008

We present a continuous electrical cell lysis chip, using a DC bias voltage to generate the focused high electric field for cell lysis as well as the electroosmotic flow for cell transport. The previous cell lysis chips apply an AC voltage between micro-gap electrodes for cell lysis and use pumps or valves for cell transport. The present DC chip generates high electrical field by reducing the width of the channel between a DC electrode pair, while the previous AC chips reducing the gap between an AC electrode pair. The present chip performs continuous cell pumping without using additional flow source, while the previous chips need additional pumps or valves for the discontinuous cell loading and unloading in the lysis chambers. The experimental study features an orifice whose width and length is 20 times narrower and 175 times shorter than the width and length of a microchannel. With an operational voltage of 50 V, the present chip generates high electric field strength of 1.2 kV/cm at the orifice to disrupt cells with 100% lysis rate of Red Blood Cells and low electric field strength of 60 V/cm at the microchannel to generate an electroosmotic flow of $30{\mu}m/s{\pm}9{\mu}m/s$. In conclusion, the present chip is capable of continuous self-pumping cell lysis at a low voltage; thus, it is suitable for a sample pretreatment component of a micro total analysis system or lab-on-a-chip.

• Journal of the Society of Naval Architects of Korea
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• v.36 no.2
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• pp.61-71
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• 1999

This paper resents a novel cargo system adapted for a sea port subjected to severe time-varying tide. The proposed system can perform loading or unloading by using a sort of hydraulic elevator associated with real-tim position control. As a preliminary phase, a small-sized model of the cargo system is designed and constructed. The model consists of three principal components ; container palette transfer(CPT) car, platform with lifting columns and cargo ship. The platform activated by the electro-rheological(ER) valve-cylinder is actively controlled to track the position of the cargo ship subjected to be varied due to the time-varying tide and wave motion. Following the derivation of the dynamic model for the platform and cargo ship motions, an appropriate control scheme incorporating time sequence and PID(proportional-integral-derivative) controller is formulated and implemented. Both the simulated and the measured control results are presented to demonstrate the effectiveness of the proposed cargo system.

• Journal of the Korean Society for Railway
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• v.18 no.1
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• pp.33-42
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• 2015

The vertical static stiffness of rail pads or baseplate pads, which are important components in rail fastening systems for track safety, is a key factor to determine the total track stiffness and a guideline of quality control in the manufacturing process. The vertical static stiffness can be checked by laboratory testing: test methods are EN 13146-9 and KRS TR 0014, which are widely used in the railway field. In this paper, to correct some problems, namely the preloading step, the unloading level, and the holding time in the loading program in the vertical static stiffness test of EN 13146-9 and KRS TR 0014, domestic and foreign test standards of pads were analyzed and then certain schemes for a vertical static stiffness test were proposed. To assess the reliability of the proposed schemes, the vertical static stiffness tests were performed with 4 pads and the validity of the test results was estimated.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 2006.06b
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• pp.331-336
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• 2006

The rail clamp is the device to prevent that a crane slips along rails due to the wind blast as well as to locate the crane in the set position for loading and unloading containers. The wedge type rail clamp should be designed to consider the structural instability and the durability because it compresses both rail side with large clamping force by the wedge working as the wind speed increases. In this research, there are two methods which are design of experiment and variation technology in used commercial software and shape optimization was performed. The optimum results obtained by the two methods are compared and examined.

• Journal of the Korean Society of Industry Convergence
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• v.26 no.2_2
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• pp.333-340
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• 2023

Environmental regulations are being strengthened worldwide to solve global warming. For this reason, interest in eco-friendly gas fuels such as LNG and hydrogen is continuously increasing. However, when adopting eco-friendly gas fuel, liquefying at a cryogenic temperature is essential to ensure economic feasibility in storage and transportation. Although austenitic stainless steel is typically applied to store cryogenic liquefied gas, structural steel can experience sudden heat shrinkage in the case of leakage in the loading and unloading process of LNG. In severe cases, the phase of the steel may change, so care is required. This study conducted Charpy impact tests on steel material in nine different temperature ranges, from room to cryogenic temperatures, to analyze the effects of cryogenic liquefied gas leaks. As a result of the study, it was not easy to find variations in ductile to brittle transition temperature (DBTT) due to the leakage of cryogenic liquefied gas. Still, the overall impact toughness tended to decrease, and these results were verified through fracture surface analysis. In summary, brittle fracture of the steel plate may occur when a secondary load is applied to steel for hull structural use exposed to a cryogenic environment of -40 ℃ or lower. Therefore, it needs to be considered in the ship design and operating conditions.