Yoon-Ki Choi

Test methods and reduction of organic pollutant compound emissions from wood-based building and furniture materials.

This paper reviews different methods for the analysis of formaldehyde and volatile organic compounds (VOCs) from wood-based panel materials for furniture and building interiors and highlights research on reduction of emission from wood-based panels that can adversely affect indoor air quality. In Korea, standard test methods have been developed to determine formaldehyde and VOC emissions from building products, and the Ministry of Environment regulates the use of building materials with pollutant emissions. Desiccator and perforator methods are being used for formaldehyde and the chamber and field and laboratory emission cell (FLEC) methods for VOC and formaldehyde emissions. The VOC analyzer is a suitable pre-test method for application as a total VOC (TVOC) emission test and bake-out is a useful method to reduce TVOC and formaldehyde emissions from furniture materials in indoor environments.

Web-Based Electronic Data Interchange Model to Improve the Callaboration of Participants in Construction Projects

Information management in construction fieldwork incurs high cost and brings about low efficiency, because construction work involves various participants and informal data that circulate among them. To overcome the problems mentioned above, information technology is being widely adopted. And, in this regard, the Korean government has been trying to promote competitiveness within the construction industry by carrying forward CALS (Continuous Acquisition and Life-cycle Support). In particular, linking and sharing knowledge and information among the participants involved has not been as efficient. The currently used EDI (Electronic Data Interchange) was developed only for each company and not for all of construction participants. Thus, a new model to achieve a more efficient methodology for

Confirmation of the performance of exfoliated graphite nanoplatelets for pollutant reduction rate on wood panel

Exfoliated graphite nanoplatelets have been used as an additive for the improvement of a variety of properties. Nowadays, it is used as an adsorbent for pollutants, especially volatile organic compounds and formaldehyde. Additionally, exfoliated graphite nanoplatelets have been used as an additive in wood composites, because wood composites have a higher thermal conductivity than timber or typical wood-based panels. Therefore, exfoliated graphite nanoplatelets have been applied to high-density fiberboard which is a core material of wood flooring for the emission rate reduction of volatile organic compounds and formaldehyde and for increasing the thermal conductivity of wood flooring in radiant floor heating systems. Volatile organic compound emissions have been reduced significantly in wood composite boards according to the addition of exfoliated graphite nanoplatelets. The properties of formaldehyde emission and thermal conductivity decreased when 2% exfoliated graphite nanoplatelets are added to high-density fiberboard. However, these properties increased with the increase in the addition of exfoliated graphite nanoplatelets from 2% to 4%.

A Study of Analysis for Impact Assessment of the Cost Risk-Factor on the Design-Build Projects based on Business Process

Recently, a delivery system has been rapidly changed in the global construction market. Also, construction projects are becoming bigger and more technology-intensive. A lot of projects have been delivered by Design-Build(DB) System; from the standpoint of cost, approximately 40% of delivered constructions by a Public Procurement Service were DB in 2009. Nevertheless, the achievement has not surpassed our expectations on management of the project cost. On the characteristic of DB, the reasons why that happens are that projects contract have been signed after the Design Development Stage; the insufficient review about new technology and up-to-date construction methods; a lack of discussion in process of design. Those reasons cause a risk of increasing Cost of the projects. In order to solve these problems, it is desirable to find Cost-increasing factors in promoting the projects and select on the order of priority for Risk-Factor with careful management. Therefore, this study analyzed the weight of each phase of the project on the authority of properties of DB project, and identified Risk-factors which is increasing the cost on the aspect of project management. Based on this analysis, the impact assessment of Risk-factor is evaluated through the Failure Mode and Effect Analysis(FMEA).

Magnetic and Thermal Properties of MoN Underlayer for Spin Valves Depending on Nitrogen Concentration

We incorporated nitrogen in the Mo underlayer and investigated the effect of nitrogen concentration on the magnetic properties and annealing behavior of the spin valve devices. The spin valve structure was Si/SiO2/Mo(MoN)(35Aring)/NiFe(21 Aring)/CoFe(28 Aring)/Cu(22 Aring)/CoFe(18 Aring)/IrMn(65 Aring)/Ta(25Aring). It is concluded that MoN underlayer is magnetically as good as Ta underlayer for N2 gas flow rate of less than 6 sccm

A Study on the Improvement of Customized Apartment Business Process

Recently, to reflect the various needs of customers in the apartment industry, the customized apartment has emerged. Also, this customized apartment is expected to expand throughout the apartment industry. From the point of the customer, customized apartments have the definite advantage of being able to guarantee more customer options. On the other hand, from the point of the project manager, there are significant issues such as construction companys management and operational issues, difficulty of decision-making with customers, frequent design changes, etc. The reasons for these issues are insufficient systematic analysis of the project, and a lack of experience of similar projects. This study analyzes the current business process of customized apartment and elicits depressed factors of the work phase. A survey and interview are conducted to achieve the waste factors using MUDA methodology; a process of the project was analyzed; and a factor of each process was identified. Also, AHP(Analytic Hierarchy Process) are used, to evaluate the waste factors in project stages. After a survey conducted on specialists in order to analyse the problem, results indicated that the problem during the customized apartment project were inefficiency due to lack of professional task force, inappropriate process and insufficient management of information about excessive design change. As a solution, This study suggests to create a professional consulting team that reflects customers needs. Based on this professional consulting team, this study will improve business organization of the customized apartment. Improved business process is suggested as project performance phase; consult - construction - interior - completion. In conclusion, this study suggests improvement plan of business process based on the research. The results of our study will provide accurate and rapid information sharing, easy management of numerous changes and high productivity of the construction company.

A Study of Customer Satisfaction Analysis in Construction Management(CM) Focus on Public Construction Managements Services

More than 10 years have been passed since the CM service was introduced in Korea. The total value of CM contract in 2013 was 4,886 billion KRW among 60 companies (performances which was evaluated and published by the Ministry of Land Center). The number of contract was increased by 50% than that of the previous year. This outcome was supported by huge-scale projects(the relocation of the U.S. and etc.) and expansion of overseas projects(Baku Olympic stadium and etc.). However, the CM industry was focusing on quantitative aspects rather than qualitative aspects. Although importance of the customer is emphasized in CM industry, CM customer service was not managed systematically. Therefore, the purpose of this study is to evaluate the customer satisfaction by creating the CM Customer Satisfaction Evaluation System. In the process of developing the system, applicable satisfaction models were considered and the list for satisfaction measurement was made. This study shows the current customer satisfaction in public CM service and has led to find which part of CM service should have been developed.

The Development of Business Information System based on BPS for Urban Regeneration Projects

Urban area has caused decline of commercial function and infrastructure because of unorganized urban development, and urban regeneration projects have appeared since 2000s in order to solve urban problems. Because urban regeneration projects have a complexation of various use, the complicated business process and unsystematic conduction work, project stakeholders are suffering from problem in conducting project. Therefore, this study suggested the necessity of business system for urban regeneration projects with analyzing situations and stakeholders. Also, this study classified business information through development of BPS in order to make information system of business process in the urban regeneration project and evaluated it after realization for information system based on BPS of urban regeneration projects. Project stakeholders will be systematically provided information about urban regeneration projects through this system and it is expected to accomplish urban regeneration projects effectively.

Application of Plywood with Water-Based Phenol-Formaldehyde Resin Impregnated Linerboards as Formwork for Concrete Structure

The front and back layers of plywood formwork consist of veneers made of Oceania timber (Shorea spp.). As the demand for Oceania timber has increased worldwide, it has become difficult to find good front and back layers for plywood. This study, therefore, has investigated plywood made with water-based phenolformaldehyde (PF) resin impregnated linerboards of different basis weights and pulp types. Manufactured plywood with water-based PF resin impregnated linerboards made of Korean recycled linerboard pulp layers, which were pressed at 140° C and 10 kg/cm2 for 3 min, had the highest internal bond strength. Furthermore, the internal bond strength of plywood with K2 linerboard was highest among all those tested. Based on the results of heat and cold cycle tests, alkali tests, abrasion tests, and boiling water tests, three types of linerboards: K2, KAC and KLB were found to be suitable for plywood formwork.

A Study How to Decide the Priority on Selecting Business Process for BPM to Attain Strategic Goal of Construction Company

Construction companies are fulfilled in according to project, and it is difficult to execute the standardized process in various construction projects. Thus many construction companies is adopting BPM(Business Process Management) that meet business process change and business improvement. However, it is difficult to apply BPM in a lump because of difference of BPM characteristics and company`s strategies. For this reason, it is desirable to select business process based on company`s priority. This study indicated need of method for selecting business process through studying current researches, and made BPA for construction company by analyzing business process in construction company. Moreover, this study indicated core business process from a point of profitability and growth view through grasping strategic goal priority. And also, it proposed criteria for process evaluation for BPM adoption, evaluated core business process, and indicated prior business process for BPM adoption.