• Journal of KIISE:Databases
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• v.34 no.3
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• pp.232-243
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• 2007

Metadata IR model has high precision and low recall because the query in Metadata IR model is strict that is, the query can express user information need exactly, while Full-text IR model has low precision and high recall because the query in Full-text IR model is a kind of simple keyword query which expresses user information need roughly. If user can translate one's information need into structured query well, the retrieval result will be improved. However, it is little possible to make relevant query without understanding characteristics of metadata. Unfortunately, most users do not interested in metadata, then they cannot construct well-made structured query. Amount of information contained in metadata is less than text information. In this paper, we suggest hybrid IR model using metadata and text which can provide users with lots of relevant documents by retrieving from metadata field and text field complementarily.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.10 no.9
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• pp.2236-2245
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• 2009

This paper proposes the process for evaluating the impact of charging the PHEV(Plug-In Hybrid Electric Vehicle) on the distribution systems, and analyzes the study results employing the actual systems as the PHEV is highly expected to increase in the automobile industries in North America in the near future. Since the charging load of the PHEV directly connected to the distribution systems would consume electric power much more than any other existing electric product of residential customers, the new modeling and process would be required to consider the PHEV in distribution systems planning. The EPRI(Electric Power Research Institute) is collaboratively conducting the impact study of PHEV on the distribution systems with power utilities in North America. This study models distribution systems and the charging load of the PHEV using OpenDSS software, and analyzes the impact of PHEV on the distribution systems by assuming various scenarios with different charging time and PHEV types.

• Proceedings of the Korea Water Resources Association Conference
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• 2015.05a
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• pp.220-220
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• 2015

Water, energy, and food security already became a risk that threatens people around the world. Increasing of resources demand, rapid urbanization, decreasing of natural resources and climate change are four major problems inducing resources' scarcity. Indeed, water, energy, and food are interconnected each other thus cannot be analyzed separately. That is, for simple example, energy needs water as source for hydropower plant, water needs energy for distribution, and food needs water and energy for production, which is defined as W-E-F nexus. Due to their complicated linkage, it needs a computer model to simulate and analyze the nexus. Development of a computer simulation model using system dynamics approach makes this linkage possible to be visualized and quantified. System dynamics can be defined as an approach to learn the feedback connections of all elements in a complex system, which mean, every element's interaction is simulated simultaneously. Present W-E-F nexus models do not calculate and simulate the element's interaction simultaneously. Existing models only calculate the amount of water and energy resources that needed to provide food, water, or energy without any interaction from the product to resources. The new proposed model tries to cope these lacks by adding the interactions, climate change effect, and government policy to optimize the best options to maintain the resources sustainability. On this first phase of development, the model is developed only to learn and analyze the interaction between elements based on scenario of fulfilling the increasing of resources demand, due to population growth. The model is developed using the Vensim, well-known system dynamics model software. The results are amount of total water, energy, and food demand and production for a certain time period and it is evaluated to determine the sustainability of resources.

• Journal of Applied Reliability
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• v.17 no.4
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• pp.280-288
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• 2017

Purpose: PBA buried in underwater requires high reliability because of its mission critical characteristic and harsh operational environment during its life cycle. Therefore, various reliability improvement activities are necessary. The defect on PBA manufacturing process have been studied, as a result, many activities and standards have been presented. However, there are less studies regarding failure pattern on physical features based on design. In this paper, we studied a possible failure patten based on physical features that is related with manufacturing process of PBA. And reliability improvement design based on PoF (Physical of Failure) were intruduced in this paper. Methods: A reliability prediction simulation were performed on the components A and B of the H system using Sherlock Software which is a PoF commercial tool from DFR solution. Solder fatigue and PTH fatigue analysis based on thermal cycling profiles and random vibration was analyzed on three earthquake response spectrum. Result: It was validated that life time and reliability improvement design through solder fatigue and PTH fatigue analysis in case of component. For compoenet B, random vibration fatigue was additionally analyzed and validated reliability for earthquakes profile. Conclusion: In design stage prior to manufacturing, PoF can be analyzed, and it is possible to make a reliability improvement/validated design using design data. This study can be applied in every design step and contribute to make more stable development product.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.38 no.4
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• pp.177-183
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• 2015

Incremental sheet metal forming is a manufacturing process to produce thin parts using sheet metals by a series of small incremental deformation. The process rarely needs dedicated dies and molds, thus, preparation time for the process is relatively short as to be compared to conventional metal forming. Spring back in sheet metal working is very common, which causes critical errors in dimensions. Incremental sheet metal forming is not fully investigated yet. Hence, incremental sheet metal forming frequently produces inaccurate parts. This paper proposes a method to minimize dimensional errors to improve shape accuracy of products manufactured by incremental forming. This study conducts experiments using an exclusive incremental forming machine and the material for these experiments are sheets of aluminum AL1015. This research defines a process parameter and selects a few factors for the experiments. The parameters employed in this paper are tool feed rate, tool diameter, step depth, material thickness, forming method, dies applied, and tool path method. In addition, their levels for each factor are determined. The plan of the experiments is designed using orthogonal array $L_8$ ($2^7$) which requires minimum number of experiments. Based on the measurements, dimensional errors are collected both on the tool contacted surfaces and on the non-contacted surfaces. The distances between the formed surfaces and the CAD models are scanned and recorded using a commercial software product. These collected data are statistically analyzed and ANOVAs (analysis of variances) are drawn up. From the ANOVAs, this paper concludes that the process parameters of tool diameter, forming depth, and forming method are the significant factors to reduce the errors on the tool contacted surface. On the other hand, the experimental factors of forming method and dies applied are the significant factors on the non-contacted surface. However, the negative forming method always produces better accuracy than the positive forming method.

• Journal of the Korean Society for Railway
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• v.10 no.5
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• pp.596-599
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• 2007

A comparative Life Cycle Assessment (LCA) among three types of Electric Motor Unit (EMU) Interior Panel (IP) was conducted. A functional unit for comparative LCA is a weight of IP for 1 EMU. It is assumed that Manufacturing stage and its upstream processes, Use stage and End of Life (EoL) stage are included in the boundary of product system. For Use stage, the weight of IP causes electricity consumption. It is assumed that aluminum IP is recycled and the other IPs are incinerated at the EoL stage. As a comparison results, aluminum IP has much larger environmental impact (5.162pt) than others (FRP IP; 4.069pt, Phenol IP; 4.053pt) even though recycling consideration is included. The manufacturing stage of aluminum IP has relative big environmental impact (1.824pt) and this point make the most important difference from other IPs (FRP IP; 0.1617pt, Phenol IP; 0.4534pt)). Despite of large weight difference between FRP IP (888.96kg) and phenol IP (316kg), the final environmental impact result has only little difference (0.016pt, 0.39%). With this result, the EMU designer can choose IP with a consideration of the environmental performance of IP.

• Journal of Navigation and Port Research
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• v.45 no.2
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• pp.61-68
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• 2021

Logistics movement using ships has been used for many centuries, but maritime accidents are still difficult to predict and they occur on a large scale. The International Maritime Organization (IMO) made it mandatory to install Electronic Chart Display and Information System (ECDIS) for safe seas, but S-57 standards applied to equipment were not updated over 30 years. In addition, it is difficult to keep the equipment up-to-date and revise standards as ships move around the world. In consideration of the limitations of S-57, the IHO developed the new standard as S-100 rather than an update of the S-57. In this study, the previously developed S-100 tool and S/W were configured as one platform and applied to the S-100 ECDIS. The platform conducts as the S-100 cycle and ecosystem from the creation of standards to release and practical use in ships. The hydrographic information standard is machine-readable as defined in S-100, and it has been validated that the latest standard can be applied using the Plug and Play (PnP) function without software system updates. It is expected that international organization such as the International Hydrographic Office (IHO) and the International Association of Marine Aids to Navigation and Lighthouse Authorities (IALA) shall develop and release standards and mariners can easily apply the latest standards to equipment through the machine-readable platform.

• Microbiology and Biotechnology Letters
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• v.49 no.2
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• pp.148-156
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• 2021

Single-chain antibodies against epidermal growth factor receptor variant III (EGFRvIII) are potentially promising agents for developing antibody-based cancer treatment strategies. We described in our previous study the successful expression of an anti-EGFRvIII scFv antibody in Escherichia coli. However, we could also observe the formation of insoluble aggregates in the periplasmic space, limiting the production yield of the active product. In the present study, we investigated the mechanisms by which growth conditions could affect the expression of the soluble anti-EGFRvIII scFv antibody in small-scale E. coli NiCo21(DE3) cultures, attempting to maximize production. The secreted scFv molecules were purified using Ni-NTA magnetic beads and protein characterization was performed using SDS-PAGE and western blot analyses. We used the ImageJ software for protein quantification and determined the antigen-binding activity of the scFv antibody against the EGFRvIII protein. Our results showed that the highest percentage of soluble scFv expression could be achieved under culture conditions that combined low IPTG concentration (0.1 mM), low growth temperature (18℃), and large culture dish surface area. We found moderate-yield soluble scFv production in the culture medium after lactose-mediated induction, which was also beneficial for downstream protein processing. These findings were confirmed by conducting western blot analysis, indicating that the soluble, approximately 30-kDa scFv molecule was localized in the periplasm and the extracellular space. Moreover, the antigen-binding assay confirmed the scFv affinity against the EGFRvIII antigen. In conclusion, our study reveals that low-speed protein expression is preferable to obtain more soluble anti-EGFRvIII scFv protein in an E. coli expression system.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.42 no.1
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• pp.1-7
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• 2019

In the modern industrial period, the introduction of mass production was most important progress in civilization. Die-casting process is one of main methods for mass production in the modern industry. The aluminum die-casting in the mold filling process is very complicated where flow momentum is the high velocity of the liquid metal. Actually, it is almost impossible in complex parts exactly to figure the mold filling performance out with the experimental knowledge. The aluminum die-castings are important processes in the automotive industry to produce the lightweight automobile bodies. Due to this condition, the simulation is going to be more critical role in the design procedure. Simulation can give the best solution of a casting system and also enhance the casting quality. The cost and time savings of the casting layout design are the most advantage of Computer Aided Engineering (CAE). Generally, the relations of casting conditions such as injection system, gate system, and cooling system should be considered when designing the casting layout. Due to the various relative matters of the above conditions, product defects such as defect extent and location are significantly difference. In this research by using the simulation software (AnyCasting), CAE simulation was conducted with three layout designs to find out the best alternative for the casting layout design of an automotive Oil Pan_BJ3E. In order to apply the simulation results into the production die-casting mold, they were analyzed and compared carefully. Internal porosities which are caused by air entrapments during the filling process were predicted and also the results of three models were compared with the modifications of the gate system and overflows. Internal porosities which are occurred during the solidification process are predicted with the solidification analysis. And also the results of the modified gate system are compared.

• Journal of Fashion Business
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• v.23 no.3
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• pp.67-84
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• 2019

Since the early 2000s, various fashion design products that use 3D printing technology have constantly been introduced to the fashion industry. However, given the nature of 3D printing technology, the flexible characteristics of material of textile fabrics is yet to be achieved. The aim of this study is to develop the optimal design conditions for production of flexible and elastic 3D printing fabric structure based on plain weave, which is the basic structure in fabric weaving using SLS 3D printing technology. As a the result this study aims to utilize appropriate design conditions as basic data for future study of flexible fashion product design such as textile material. Weaving structural design using 3D printing is based on the basic plain weave, and the warp & weft thickness of 4mm, 3mm, 2mm, 1.5mm, 1mm, and 0.7mm as expressed in Rhino 6.0 CAD software program for making a 3D model of size $1800mm{\times}180mm$ each. The completed 3D digital design work was then applied to the EOS SLS Machine through Maker ware, a program for 3D printer output, using polyamide 12 material which has a rigid durability strength, and the final results obtained through bending flexibility tests. In conclusion, when designing the fabric structure design in 3D printing using SLS method through application of polyamide 12 material, the thickness of 1 mm presented the optimal condition in order to design a durable digital textile structure with flexibility and elasticity of the 3D printing result.