Jun Iwamatsu

• Doctor of Engineering
• Senior Research Fellow at Research Institution on Building Cost (RIBC)

In the many construction marketplaces in Japan, number of participants per bid has gradually decreased over the long term. Especially in the Tokyo metropolitan area, the number of single-bids has gradually increased. And that exposed some competition policy issues. The Tokyo Metropolitan Government had tried to cancel some single-bids in one-year p...

- Trends in bid data disclosure in Japan - About the data to be analyzed in the research - More than 20 years of outlines of the conditions in public buildings bidding competition - Changes in the number of bidders and successful bid rate - time series analysis - About the one-party or single bidding issue

Anyone can calculate the building unit price obtained from the building start statistics relatively easily. It is useful for capturing a macro view of the building market, and there is a great need for its use in architectural planning. However, if the stratification of the attributes of the observed data is extremely advanced, the number of data m...

First in the study, some inter-country input-output tables (ICIOs) that can be publicly available have been searched. As a result, it was decided to use WIOD (the World Input-Output Database) which have been published recently under the EU's fund. This paper is an analysis that focused on the construction industry, which is one of the 35 industrial...

One of the major factors that make the Japanese construction production system vulnerable is the multi-layering of subcontractors. It has been pointed out frequently that business transactions in such multilayered systems often lead to pricing and scheduling difficulties due to the nature of the relationship between contractors and subcontractors....

Today's construction market and industry are in a state of chaos throughout the world. The globalization of this market demands that national governments and construction contractors associations, as well as construction contractors, set in place effective strategies to overcome such turmoil. This paper examines the strategies used by major contrac...

In the recent Japan, some statistics and results of investigations which cover plenty of construction companies became available in the form of digital data. This research uses them, and analyzes and understands the overall picture of Japan's construction industry. Especially in this analysis, the Business-Evaluation results (BERs) created and rele...

In the recent Japan, some statistics and results of investigations which cover plenty of construction companies become available in the form of digital data. This research uses them, and analyzes and understands the overall picture of Japan's construction industry. Especially in this analysis, the Business-Evaluation results (BERs) created and rele...

This paper analyzes the changes in the profitability and productivity indices of Japanese construction enterprises in recent years. The analysis used a very large database, called the Business Evaluation Results (BERs), which is compiled and published under the Construction Business Act. The data used in this analysis reflects the business performa...

In order to know the consciousness of Japanese major construction company's bidding behaviors, a question paper survey is conducted which is similar to three previous experiential study papers of U.S. and U.K. The questionnaires are made to unique to Japanese domestic circumstances. The main questionnaire is the importance evaluation to 36 factor k...

In the recent Japan, some statistics and results of investigations which cover plenty of construction enterprises become available in the form of digital data. This research uses them, and analyzes and understands the overall picture of Japanese construction industry. Especially in this analysis, the Business Evaluation results created and released...

The shortage of skilled labours and the successors in the construction industry poses previously a very large problem. However, the actual working conditions of skilled labours are not grasped correctly. Therefore, the radical remedy of this problem is not shown. In the research presented so far, authors have pointed out the actual condition that s...

Specialty contractors' survey has been carried out and the reinforcing bar subcontractor A's curriculum vitae has been obtained. Statistical analysis of 650 contracts information for the past ten years is conducted. Although subcontractor A is comparatively big, and so the analysis results can not be generalized, many interesting points are made ou...

Various numbers of bidders exists in public building and/or construction works. Practically in Japan, exceedingly 10 bidders are participating in one bid. It is conceivable that number of bidders in one bid affects certain amount of influence on the competition. With using Friedman's model or Gates' model, which are known as maximum expected value...

Increasing attention is today being focused on the issue of dispute resolution in the Japanese construction sector. Disputes were infrequent under the traditional contract agreement system. However, against the background of a shrinking construction market, owners, contractors, builders, engineers, subcontractors, and suppliers are seeking higher p...

In the Japanese construction sector where the bidding system has been recently reformed, the data of the tender results in areas of public construction works and/or consultancy services are now being made open, enabling objective analysis of such data from various viewpoints. In this research, such open data of a nation-wide coverage in the last tw...

In the Japanese construction sector where the bidding system has been recently reformed, the data of the tender results in areas of public construction works and/or consultancy services are now being made open, enabling objective analysis of such data from various viewpoints. In this research, such open data of a nationwide coverage in the last two...

As the infrastructure of Japan’s economy should grow up on the total output of its construction industry, there should be a strong demand for its high productivity so that its national economy could stay healthy. Yet, the construction industry has been generally understood as one field where sizable improvement of the labour productivity can hardly...

With this research we did the statistical analysis regarding the bidding strategy of the construction enterprises, by using about each 10,000 cases of disclosure data of the two organization's public works mainly carried out in the fiscal year 2000----the Ministry of Land, Infrastructure and Transport (MLIT; the former Ministry of Construction) and...

The risk in terms of works due to dispersion in efficiency of construction works are analyzed using data in actual construction and Monte Carlo simulation method with PERT model. The improvement of production efficiency requires introduction of risk concept and theory of constraints (TOC) in schedule control. Especially, optimization of the whole s...

This statistical research is for the understanding of the bidding strategy by analyzing the tender results that has come to be disclosed in Japan recently. The used data is about 4,000 occurrences of tenders on 398 public works that has been ordered in the Regional Construction Bureau of the Ministry of Construction in the spring of 1999. As a resu...

After 1990, there has been many studies about international comparison of building cost on houses. First, we surveyed some typical studies which compared them between Japan and USA, and analyzed the results by using 'purchasing power parity'(PPP). Second, we pointed out the difficulty for international comparison in this field, and proposed to deve...