Chijoo Lee

Life-Cycle Cost Analysis on Glass Type of High-Rise Buildings for Increasing Energy Efficiency and Reducing CO 2 Emissions in Korea

As the heights of high-rise buildings increase, their building area and elevation area also increase, consequently increasing their yearly energy consumption. Energy efficiency has become an even more important issue, especially when glass is used for a buildings exterior. In this study, the life-cycle cost (LCC) of the exterior glass of high-rise buildings was analyzed from the perspective of energy efficiency and CO2 emissions. First, the LCC was analyzed according to changes in the selected types of glass. Reflective + Low-E (Type 1), double Low-E + Argon (Type 2), and triple Low-E + Argon (Type 3), which satisfy green building certification criteria and were used in the past for high-rise buildings in Korea, were selected as the exterior glass types. These types of exterior glass were applied to a case building and compared with the Low-E glass that was the existing glass type of a case building. The economic benefit of selected glasses for 40 years was greater in the order of Type 1, Type 3, and Type 2 compared to the existing glass. Second, these types of glass were applied to each orientation of the building. By changing the glass according to building orientation it is shown that in the east, west, and north, Type 1 was most economical, whereas Type 3 was most economical in the south. The results of this study will contribute to the improvement of energy efficiency, CO2 emissions reduction, and cost efficiency of future high-rise buildings. DOI: 10.1061/(ASCE)CO.1943-7862.0000502.

A Study on a Method for Composing a Portfolio for REITs Investment Using Markowitz`s Portfolio Model

Domestic construction companies suffer from the difficulty in financing in the wake of economic slump at home and abroad. In the periods of this economic slump, which hit the nation REITs, the facilitator of fluid financing and the stimulating of construction economic, has increasingly been expanded since its introduction in 2001. But, REITs relatively falls behinds any other nations, in terms of its growth speed and marketing volume. The purpose of this research thesis is to suggest the method for composing a portfolio using Markowitz portfolio selection models for stimulating REITs. Main contents are as follows. First, the thesis made the comparative analysis on profit increase in REITs investment in application of models by Markowitz and REITs derivatives from 2007/07/03 to 2008/07/21 during investment analysis periods. The result showed that total profits by Markowitz model amounted to about 10 percent higher than average profits of REITs derivatives. Second, this thesis made the analysis on sensitivity of data-gathering and portfolio change periods of the existing profits, in order to measure the both periods and yield optimum profits. The six month data-collecting periods of profits accounted for some 16% higher profits than profits of REITs derivatives. In case when the two week periods of portfolio change accounted for some 11% higher profits than profits of REITs derivatives.

Relation Analysis Between REITs and Construction Business, Real Estate Business, and Stock Market

Even though REITs (Real Estate Investment Trusts) are listed on the stock market, REITs have characteristics that allow them to invest in real estate and financing for real estate development. Therefore REITs is related with stock market and construction business and real estate business. Using time-series analysis, this study analyzed REITs in relation to construction businesses, real estate businesses, and the stock market, and derived influence factor of REITs. We used the VAR (vector auto-regression) and the VECM (vector error correction model) for the time-series analysis. This study classified three steps in the analysis. First, we performed the time-series analysis between REITs and construction KOSPI(The Korea composite stock price index) and the result showed that construction KOSPI influenced REITs. Second, we analyzed the relationship between REITs and construction commencement area of the coincident construction composite index, office index and housing price index in real estate business indexes. REITs and the housing price index influence each other, although there is no causal relationship between them. Third, we analyzed the relationship between REITs and the construction permit area of the leading construction composite index. The construction permit area is influenced by REITs, although there is no causal relationship between these two indexes, REITs influenced the stock market and housing price indexes and the construction permit area of the leading composite index in construction businesses, but exerted a relatively small influence in construction starts coincident with the composite office indexes in this study.

A system to detect potential fires using a thermographic camera

This paper describes a fire monitoring system, based on a thermographic camera, for electrical appliances in interior spaces. These appliances are at particular risk because they are vulnerable to the carelessness of users (46% of electrical appliances fires are caused this way). The system compromises a thermographic camera, rotating on a two-axis robotic arm, controlled by a fire monitoring algorithm that detects the appliances’ status. Once the system’s accuracy and ability to identify the status of each appliance had been tested, the camera’s rotation sequence was planned. To achieve the best efficiency, bearing in mind that fires can break out very quickly, the sequence was based on the distance between monitored appliances. Over a nine-hour period, monitoring six appliances, the proposed method resulted in about 295 (about 7%) more rotations than those produced by a method of arbitrary ordering. This effectiveness increases when more appliances are monitored over greater periods. The system’s main contribution to fire safety is the application and full utilization of the thermal camera, detecting the beginnings of a fire before it can break out.

Method to reduce the gap between construction and IT companies to improve suitability before selecting an enterprise system

Abstract This study proposes a method to reduce the perception gap between the system required by construction companies and the system proposed by information technology (IT) companies during the negotiation process before selecting an enterprise system. The goal of the proposed method is to increase the developed system’s suitability to a construction company. First, a set of selection factors was determined and defined. The gap between construction companies’ requirements and the IT companies’ offerings was then analyzed. Then a method to reduce the gap to improve suitability before selecting the system was described. The applicability of the method was tested by comparing selected and non-selected cases from two previous projects. The analysis result showed that the method is highly applicable to both construction companies and IT companies. Construction companies can apply the method to select a preferred system on the basis of suitability; and during the negotiation process before system selection, IT companies can apply the method to analyze whether a system satisfies the specific requirements of a construction company. The set of defined selection factors is also applicable to the evaluation criteria of the enterprise system.

A Priority and Impact Factor Analysis of Construction Management Tasks for Decreasing Change Orders and Defect Repairs in Cancer Treatment Center Projects

The complexity of constructing medical institutions is higher than that of general buildings, and many change orders in the design and defect repairs in the construction phase are required due to strict government regulations. The priority control of constructions and impact factors of medical institutions were analyzed in this study, and difficulties in the control in the design and construction phase were identified. First, the priority management factors that were identified were as follows: architecture, facilities, and electricity. Second, 1) priority management in constructions and factors resulting in change orders and 2) priority management in constructions involving defect repair were analyzed. Third, the importance recognized by the construction managers were analyzed. The priority management in constructions and factors that were recognized by the construction manager were deducted as having low importance, although there were many change orders and defects. The work of finishing, wall building, joining, office automation and communication function, and lighting were analyzed in the design phase, and waste, the office automation and communication function, ceilings, contamination control, and plumbing were analyzed in the construction phase. The results showed that there will be a decrease in change orders and defects if the concentration of the manager was elevated and priorities were managed.

Method for Composing a Portfolio for REITs Investment Using Markowitz`s Portfolio Model

Domestic construction companies are suffering from financing difficulties in the wake of the economic slump in Korea and abroad. During this economic slump, real estate investment trusts (REITs), facilitators for improving financing and stimulating construction businesses, have increasingly expanded since their introduction in 2001. However, in terms of growth speed and marketing size, Korean REITs are falling behind those of other nations. The purpose of this study is to suggest a method for composing a portfolio using the Markowitz portfolio selection model to stimulate REITs. The main contents are as follows. First, a comparative analysis was conducted of increased REIT profit with the application of the Markowitz model and the average REIT profit rate from July 3, 2007, to July 21, 2008, during the investment analysis periods. The results showed that the total profit rate from the Markowitz model was about 10% higher than the average REIT profit rate. Second, the sensitivity was analyzed according to the portfolios data-gathering and replacement cycle to measure the optimum cycle and yield. The six-month profit data collection period showed about 16% higher profits with the Markowitz model than with the REITs. The two-week portfolio change period resulted in about 11% higher profits with the Markowitz model than with the REITs