• Transactions of the Korean Society of Automotive Engineers
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• v.22 no.2
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• pp.60-66
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• 2014

A control oriented model of the Lean $NO_x$ trap (LNT) was developed to determine the timing of $NO_x$ regeneration. The LNT model consists of $NO_x$ storage and reduction model. Once $NO_x$ is stored ($NO_x$ storage model), at the right timing $NO_x$ should be released and then reduced ($NO_x$ reduction model) with reductants on the catalyst active sites, called regeneration. The $NO_x$ storage model simulates the degree of stored $NO_x$ in the LNT. It is structured by an instantaneous $NO_x$ storage efficiency and the $NO_x$ storage capacity model. The $NO_x$ storge capacity model was modeled to have a Gaussian distribution with a function of exhaust gas temperature. $NO_x$ release and reduction reactions for the $NO_x$ reduction model were modeled as Arrhenius equations. The parameter identification was optimally performed by the data of the bench flow reactor test results at space velocity 50,000/hr, 80,000/hr, and temperature of $250-500^{\circ}C$. The LNT model state, storage fraction indicates the degree of stored $NO_x$ in the LNT and thus, the timing of the regeneration can be determined based on it. For practical purpose, this model will be verified more completely by engine test data which simulate the NEDC transient mode.

• The KIPS Transactions:PartD
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• v.8D no.4
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• pp.361-366
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• 2001

As growing the number of Webs, the total amount of accessible information has been greater than ever. To storage and retrieve the vast information on the Webs effectively, many researchers have been made utilizing XML (extensible Markup Language). In this paper, we propose an effective method of representation and retrieval mechanism for the structured retrieval of the XML documents : (1) the fixed sized LETID (Leveled Element Type ID) that contains the information of elements such as parent node, sibling nodes, and identical sibling nodes, and the hierachical information of current node, and (2) content index, structure index, attribute index model, and the information retrieval algorithm for the structured information retrieval. With our methods, we can effectively represent the structured information of XML documents, and can directly access the specific elements by simple operations to process various queries.

• Proceedings of the Korea Database Society Conference
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• 1997.10a
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• pp.455-462
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• 1997

SGML(Standard Generalized Markup Language) is the ISO standard fer describing the logical structure of documents and is also adopted as the CALS standard for document description. Since then, there have been growing interests in SGML application in a variety of fields. However because SGML doesn't provide a standard method for describing various processing informations, ie, formatting and transformation, most applications have applied methods that are system dependent. Recently, ISO defined DSSSL(Document Style Semantics and Specification Language) as a standard mechanism to specify the formatting, transformation and retrieval of structured documents. Therefore, in this paper, we present a DSSSL processing system far style control of structured documents such as SGML documents. The system processes DSSSL style sheet that describes layout of documents and browses the result of its application to a SGML document. We have conducted tests on a lot of SGML documents and DSSSL style sheets successfully. Now, we are developing the SGML document management system that supports creation, editing, storage and retrieval of SGML document based upon the DSSSL processor and the SGML parser which we have developed.

• Journal of the Korean Society of Systems Engineering
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• v.19 no.2
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• pp.59-73
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• 2023

Due to the steady growth of the online shopping market and contact-free consumption, the volume of parcels in South Korea continues to increase. However, there is a lack of manpower for delivery workers to handle the growing parcel volume, leading to frequent accidents related to delivery work. As a result, the government and local authorities strive to enhance last-mile logistics efficiency. As one of these measures, unmanned parcel storage lockers are installed and utilized to handle last-mile deliveries. However, the existing parcel storage involves the inconvenience of couriers having to put each parcel in each locker, and this is somewhat insufficient to relieve the workload of delivery workers. In this study, we propose parcel storage devices that use active loading technology to minimize the workload of delivery workers, extract operation risk factors to apply this system to actual sites, and establish risk reduction methods based on the ALARP concept. Through this study, we have laid the groundwork for improving the safety of the system by identifying and proposing mitigation measures for the risk factors associated with the proposed parcel storage devices utilizing active loading technology. When applied in practical settings in the future, this foundation will contribute to the development of a more efficient and secure system. By applying the ALARP concept, a systems engineering technique used in this research, to the development and maintenance of storage devices leveraging active loading technology, it is thought to make the development process more systematic and structured. Furthermore, through the risk management of the proposed system, it is anticipated that a systematic approach to quality management can be employed to minimize defects and provide a stable system. This is expected to be more useful than the existing unmanned parcel storage devices.

• Journal of Information Technology Services
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• v.14 no.3
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• pp.197-215
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• 2015

Recently, many internet users are using cloud computing. Users can manage, store and share their data and information by using personal cloud storage. In this paper, we aim to figure out influencing factors on personal cloud storage selection. The causal relationship between factors were identified through a importance analysis by using AHP(Analytic Hierarchy Process). AHP is a structured technique for organizing and analyzing complex decisions, based on mathematics and psychology. Research model consists of upper factorsincluding system factor, service factor and user factor. 12 lower factors and 6 alternatives were also analyzed. Asa result, system factor of 3 upper factors was found as the most important factor. Purpose-coincidence, security andaccessibility were top 3 factors among lower factors. N drive showed top importance value. We also conducted ANOVAby classifying 4 groups according to gender, age, currently used cloud and cloud to use. The results of this researchcan be useful guidelines for cloud computing industry.

• The Journal of Asian Finance, Economics and Business
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• v.8 no.10
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• pp.269-283
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• 2021

The government policies and initiatives to guarantee sustainable energy and clean environmental conditions contributed to the introduction of green technology electricity appliances in the market. This study sought to determine the physiological and socio-economics-demographic factors driving residential electricity consumers to use green technology electricity appliances, mainly solar PV, smart meter, electric vehicle, and battery storage technology. By understanding consumer intention, the investors of solar PV, battery storage, electric vehicle, and smart meter can estimate the demand and upscale the market for the corresponding products. For that purpose, the intention to use the solar PV, smart meter, electric vehicle, and battery storage function is developed by utilizing the combination of the theory of planned behavior, technology acceptance, and reasoning action. A reliable and valid structured online questionnaire and stepwise multiple regression are used to identify the possible factors that drive consumer behavior intention. The results show that the social influence, knowledge on RE, and perceived price significantly influence residential consumers' willingness to adopt the technologies offered. The findings of this study suggest that the involvement of NGOs, public figures, and citizens' cooperation are all necessary to spread information about the government's objectives and support Malaysia's present energy and environmental policies.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2002.07b
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• pp.801-804
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• 2002

Electrochemical capacitors are becoming attractive energy storage systems particularly for applications involving high power requirements such as hybrid systems consisting of batteries and electrochemical capacitors for electric vehicle propulsion. Both of amorphous cobalt oxide and manganese dioxide were prepared by sol-gel process reported in our previous work. Nanostructured supramolecular oligomer of 1,5-diaminoanthraquinone(DAAQ) coated metal oxides were successfully prepared by electrochemical oxidation from an acidic non-aqueous medium. We established process parameters of the technique for the formation of nano-structured materials. Furthermore, improved the capacitive properties of the nano structured metal oxide electrodes using controlled solution chemistry. $CoO_2$ and $MnO_2$-based composite electrode showed relatively good electrochemical behaviors in acidic electrolyte system with respect to specific capacity and scan rate dependency.

• Journal of Electrochemical Science and Technology
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• v.7 no.1
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• pp.1-12
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• 2016

The production of oxygen and hydrogen from solar water splitting has been considered to be an ultimate solution for energy and environmental issues, and over the past few years, nano-sized semiconducting metal oxides alone and with graphene have been shown to have great promise for use in photocatalytic water splitting. It is challenging to find ideal materials for photoelectrochemical water splitting, and these have limited commercial applicability due to critical factors, including their physico-chemical properties, the rate of charge-carrier recombination and limited light absorption. This review article discusses these main features, and recent research progress and major factors affect the performance of the water splitting reaction. The mechanism behind these interactions in transition metal oxides and graphene based nano-structured semiconductors upon illumination has been discussed in detail, and such characteristics are relevant to the design of materials with a superior photocatalytic response towards UV and visible light.

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 2000.04a
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• pp.167-170
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• 2000

Recently the sub-micron structured substrates of 0.74 ${mu}ell$ track pitch and 800 $\AA$groove depth are required for DVD-RAM and the track pitch is expected to be narrower as the need for the information storage density is getting higher. For the accurate replication of the land-groove structure in the stamper to the plastic substrates it is important to control the injection -compression molding process such that the integrity of the replication for the land-groove structure is maximized. in the present study polycarbonate substrates were fabricated by injection comression molding and the land-groove structure regarded as one of mold temperature and the compression pressure on the integrity of the replication were examined experimentally. An efficient design methodology using the response surface method (RSM) the central composite design(CCD) technique and the analysis-of-variance (ANOVA) was developed to obtain the optimum processing conditions which maximize the integrity of the replication with a limited number of experiments.

• Nano
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• v.13 no.12
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• pp.1850138.1-1850138.6
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• 2018

Two-dimensional (2D) or layered materials have a great potential for applications in energy storage, catalysis, optoelectronics and gas separation. Fabricating novel 2D or quasi-2D layered materials composed of relatively abundant and inexpensive atomic species is an important issue for practical usage in industry. Here, we suggest the layer-structured AlOOH (Boehmite) as a promising candidate for such applications. Boehmite is a well-known layer-structured material and a single-layer can be exfoliated from the bulk boehmite by breaking the interlayer hydrogen bonding. We study atomic and electronic band structures of both bulk and single-layer boehmite, and also obtain the single-layer exfoliation energy using first-principles calculations.