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Funder: European Union's Horizon 2020, Funder: European Union; Id: http://dx.doi.org/10.13039/501100000780, A simple, large area, and cost-effective soft lithographic method is presented for the patterned growth of high-quality 2D transition metal dichalcogenides (TMDs). Initially, a liquid precursor (Na2 MoO4 in an aqueous solution) is patterned on the growth substrate using the micromolding in capillaries technique. Subsequently, a chemical vapor deposition step is employed to convert the precursor patterns to monolayer, few layers, or bulk TMDs, depending on the precursor concentration. The grown patterns are characterized using optical microscopy, atomic force microscopy, Raman spectroscopy, X-ray photoelectron spectroscopy, scanning electron microscopy, and photoluminescence spectroscopy to reveal their morphological, chemical, and optical characteristics. Additionally, electronic and optoelectronic devices are realized using the patterned TMDs and tested for their applicability in field effect transistors and photodetectors. The photodetectors made of MoS2 line patterns show a very high responsivity of 7674 A W-1 and external quantum efficiency of 1.49 × 106 %. Furthermore, the multiple grain boundaries present in patterned TMDs enable the fabrication of memtransistor devices. The patterning technique presented here may be applied to many other TMDs and related heterostructures, potentially advancing the fabrication of TMDs-based device arrays.

본 논문은 YOLO(You Only Look Once)와 깊이 카메라를 이용한 차량과 보행자 간 사고방지 시스템을 제안한다. 딥러닝 기반의 YOLOv2-tiny를 이용한 차선과 보행자의 인식정보를 기반으로 보행자가 차도로 들어오는 상황에서 사용자에게 사전에 위기 상황을 알려준다. 기존의 관련 연구에서 사용한 이미지 처리 방식은 알고리즘이 복잡하므로 제안하는 시스템은 딥러닝을 이용하여 시스템 복잡성을 개선하였다. 또한, 딥러닝을 이용하여 실시간으로 물체 인식을 이용해 차선과 보행자를 동시에 인식했다. 그리고 점선을 이용하여 현재 주행 중인 차선을 확인하였다. 보행자와 사용자 간의 거리를 계산하기 위해 깊이 카메라를 사용하였으며 사고 상황 인식 알고리즘을 개발하였다. 본 시스템은 2차선을 기준으로 자동차 주행 시 보행자 충돌 사고를 중점으로 구현하였다. 마지막으로 실험 결과를 통해 제안한 시스템의 인식 정확도를 확인할 수 있으며 향후 연구 방향에 대해 논의한다.

This paper proposes a nuclear power plant monitoring system using drones. Existing surveillance systems have a disadvantage in that manpower is wasted due to the blind spots of fixed observatories and CCTVs, and it is impossible to quickly respond to situations. The proposed system detects motion winners and suspicious vehicles around nuclear power plants by using object detection technology using thermal imaging cameras and autonomous flight technology and also measures radiation levels and temperature data using Geiger counters and temperature sensors. Data can be transmitted through the 5G/LTE module and monitored in real-time.

Many international public&ndash, private partnership projects have suffered from frequent project pending status or failure because of dissimilar interests among stakeholders over projects&rsquo, long development period. Thus, this study compares the perception gaps of 27 risks between Korean construction investors and Korean financial investors depending on different development phases of international public&ndash, private partnership projects. In the project selection phase, construction investors and financial investors show few risk perception gaps. However, in the bid and proposal phase, they perceive many risks differently: construction investors tend to perceive the construction risk and financial risk as more important, whereas financial investors perceive stakeholder risk and country risk as more significant. This study also discusses the causes of risk perception gaps from three perspectives: (1) time-dependent risk, (2) risk exposure period, (3) risk transfer and responsibility. These findings will be helpful in recognizing the dynamic risk perception gaps between two leading investors for the sustainable development and investment of international PPP projects.

Inattentional blindness (IB) is a popular human error associated with selective attention or inattention. It can be depicted as an individual’s failing to notice or recognize a visual object or event due to a lack of active attention in a given situation. Dynamic situations at construction sites often can lead to IB, which can cause failure of safety risk perception (FSRP) on hazards and lead to potential accidents. Few studies have focused on the importance of the IB concept in the construction industry. To overcome this gap, 53 supervisors participated in an experiment to analyze the performance of IB in FSRP and safety knowledge-related factors that affect IB and FSRP to establish practical safety management strategies. The results show that IB accounted for 50% of FSRP, validating the importance of IB. Other factors, such as certified training and frequent exposure to accidents, also had positive impacts on reducing IB. Certification and external training showed positive impacts in the low-experience group but not on the high-experience group. Based on these findings, the IB concept should be considered when addressing construction safety management. Practical safety management strategies to improve IB should be applied differently according to the supervisor’s experience.

This paper presents road cracks detection implementation to help the road inspectors to easily identify damages on the road. Sometimes due to earthquake cracks appears on the road and identification of damages on the road is required. Identifying road cracks manually during the inspection is a tedious and difficult task. The formation of own data set is a time-consuming and laborious task. Own created data set is labelled with the improvements in the YOLOv3 tiny is finished and compared to better detect the cracks on the road. Both models performance is benchmarked in respect of accuracy and MAP (mean average precision). It is observed in testing phase, the improved tiny version of YOLO performed better in terms of MAP and accuracy. This road cracks detection system can be implemented in UAV or vehicle to detect road cracks using camera vision in Real-Time for the inspection of road.

The advancement of natural language processing and text mining techniques facilitate automatic non-trivial pattern extraction and knowledge discovery from text data. However, text-based research has received less attention compared to image- and sensor-based research in the construction industry. Hence, this paper performs a comprehensive review to understand the current state and future insights of text analytics focusing on the data source and analysis method. This study identifies various kinds of text data sources from project documents as well as open data in the websites. In addition, the review finds that the ontology- and rule-based approach has been dominant, at the same time, recent research has attempted to apply the state-of-the-art machine learning methods. It is envisioned that there are potential advancements in construction engineering and management based on the latest text analysis methods along with the enriched data by the digital transformation.

Traditionally, conflict management in construction projects has focused on disagreement among internal stakeholders, such as employer, contractors, and subcontractors. However, as social consciousness and personal welfare demands increase, social conflicts among external stakeholders, such as local residents, local and central governments, and NGOs, have become more critical factors in enhancing project viability. In Korea, these conflicts have an impact of US $70 billion annually on social costs. To alleviate social conflicts and costs, this study aims to propose a conflict management framework based on twenty-two representative public construction projects. This study identifies and frames the various causes, impacts, and resolutions of conflicts through the case history of project viability. Through these findings, five types of conflict scenarios were derived: project termination, early mitigation, late mitigation, project enforcement, and late occurrence. Furthermore, this study suggests root causes, pathway of conflict propagation, and characteristics of each conflict scenario, which will assist project stakeholders in developing sustainable management for conflict solutions in line with each project's unique situation.

The escalating number of aging sewer pipes necessitates an infrastructure asset management approach to achieve an efficient budget allocation for maintenance. This study suggests a risk-based prioritization framework for sewer pipe inspection considering the predicted condition of sewer pipes and the criticality of the economic, social and environmental impacts associated with them. The results from both models can be used to evaluate the risk of sewer pipes by classification into risk groups. A risk matrix is used for the classification, and it divides the sewer pipes into five risk groups. The results of this study show an improvement in the accuracy of finding sewer pipes in a bad condition using this framework. The condition prediction model can successfully find sewer pipes with a bad condition with over 70% precision. High-risk sewer pipes are highlighted using the differences in the environmental features as well as in the physical features associated with other sewer pipes. Additionally, through the combination of both the condition and criticality of sewer pipes, the framework systemically prioritizes needed maintenance for sewer pipes with a very bad condition. This prioritization framework is expected to help the process of deciding which sewer pipes should be prioritized within a constrained budget.

Despite the huge increase in international construction revenue for Korean construction firms during the last decade, only 8% of the overall international construction revenue has been executed by small and medium-sized construction companies (SMCCs). In addition, Korean SMCCs yields lower profits rather than large construction companies. This is due primarily to the fact that SMCCs, as subcontractors, are generally hampered by lack of financial and technical capabilities, shortage of experience, and lack of information. The low profit eventually affects both general contractors and project performance as a whole. The aim of this research is to create a framework that considers the risks of subcontractors in international construction projects to allow them to create a win-win strategy. The framework considers two perspectives: the level of the subcontractor’s performance and the interface risks between the general contractor and the subcontractor. The performance is assessed using the cost, schedule, and quality of the project’s outcome. By using 77 risks identified as relevant, a correlation analysis is performed to determine the critical risks from both perspectives. The results are found to create a strategy matrix that considers both the degree of partnership and the performance of the subcontractor. This research is expected to support industry practitioners in developing a win-win strategy, which will eventually provide them with successful entry into international construction projects.

Construction enterprises have performed various projects such as buildings, infrastructure and plant projects in the international market. Among these, the plant project’s amount of orders accounted for about 68.9% of all. However, because of the enterprises won a contract with a low-budget for plant project in the last 10 years, the profit has dropped dramatically. And it is forecasted that there are extreme competition for bid award of plant projects because of the current falling oil prices and raising interest rates. In this circumstance, the comprehending of enterprises strength and weakness must be a priority to get a sustainable competitive advantage. Therefore this research suggests the enterprises’s capability assessment framework and it is in order to diagnose the korean construction enterprises capabilities. The framework is based on the VRIO model that is on the basis of resource based theory. First, the capability assessment indices and their importance and priority that based on the life-cycle of plant project is deducted by literature review and survey. Second, the 5 point likert score applied VRIO survey is conducted to diagnose the enterprises and quantified the survey result using the fuzzy theory. Lastly, the competitive implication and capability assessment are deducted.

The effect of ‘supply chain management’ can be leveraged when benefits of collaboration within and beyond the capacities of individual organizations are witnessed. One of the primary tasks in reducing total supply chain costs is to understand where the costs occur in a supply chain and how each activity impacts the total supply chain costs. Most supply chains in construction usually involve multiple entities, each one in a different process. A rebar supply chain is one example where many entities are involved in different processes. The supply chain coordinator needs a supply chain cost model, which shows how each activity impacts all supply chain costs to reduce the total costs. The research suggests a supply chain cost model using time-driven activity-based costing. The proposed cost model was applied to a building construction project, followed by sensitivity analysis identifying critical activities. This method can be adapted to analyze other fragmented material supply chains in the construction industry.

International construction market have quantitatively increased and have reached up to 700 Bil. US$ through active effort of construction firms and government. In spite of this increase, substantiality issue has been constantly disputed due to qualitative problems such as lack of capability and technical shortage. To overcome these problems, many methods in performing quantitative growth and qualitative substantiality of overseas construction are being researched which showed that selection of subcontractors in general contractor is regarded as a very important success factor. However, it is difficult to make a reasonable decision for selecting the subcontractors due to the lack of evaluation standards and reliability. This study proposes an improved evaluation system through adjustment of the evaluation indicators using correlations analysis and multiple regression analysis with pre-qualification and performance evaluation of 121 firms in 6 countries. Keywords : Subcontractor, Pre-qualification, Performance Evaluation, Correlation Analysis, Multiple Regression Analysis

This work was supported by a Korea Science and Engineering Foundation (KOSEF) grant and funded by the Korean government (NRF-2015R1A2A1A09007327). This research was partially supported by The George Washington University’s Center for International Business Education and Research (GW-CIBER).

Many countries use financial aids to expedite public-private partnership (PPP) projects, depending on their financial status and/or demand for additional infrastructure. Minimum revenue gua...

In the recent years, Korean construction companies have been awarded 680 billion USD in the oversea projects which lead to a successful quantitative growth. However, due to the lack of capability in the core technology and project management compared to the leading companies, in addition to low-price bidding, massive deficit projects have caused problems to the companies. In order to overcome the limitations of the lack of capabilities, the term constructability has been researched recently by developed countries to apply in the practical use. The concept of constructability must be applied for Korean companies to compete in the EPC construction projects. The term constructability is defined as the factor that affect the overall construction process of a project which is defined by the ease of construction and to secure the project quality. Therefore, this study aims to develop a constructability assessment model using the structural equation to assess the factors that affect the constructability in the design and construction stage. The purpose of using the structural equation is to analyze the direct and indirect correlation between each factor that affects the international construction projects. Total of 8 latent variables and 34 measured variables are derived through literature review, corporate reports, experts` interview and surveys. The result of the model suggests the constructability factors that are to be managed the most efficiently to reduce cost, time and improve the quality as well as a countermeasure strategy to successfully execute the target international construction projects.

Finding competent collaborators while executing construction projects overseas is of paramount importance for project success. The partner choice and project performance cannot be understood only from an economic viewpoint because it is constrained by the firms’ embeddedness in social relations. Based on this premise, this paper provides not only a theoretical explanation of the impact of structural and relational embeddedness on firms’ economic behaviour and outcomes, but also empirical evidence by analysing the collaborative process among Korean construction firms working overseas during the past 18 years. Three conclusions are drawn. First, the inter-firm network, at least asymptotically, has scale-free network properties with variance. Second, the network retained endogamic characteristics in that a great majority of smaller firms had worked with only one large firm, forming strong subgroups. Last, there is a plausible evidence of the impact of both structural embeddedness and relational embeddedness on profits.

Since plant facilities including liquefied natural gas (LNG) plants pose accident risks, most risk studies have been focusing on public security risks and safety requirement. However, design and construction of LNG plants are also vulnerable to considerable schedule delay and cost increase due to its distinct characteristics such as the monopolized FEEDs technology, low-temperature and high-pressure equipment, and a large number of concurrent activities and participants. Hence, it is imperative to develop an efficient risk management tool which could support contractors' risk analysis and control in the design and construction phase. This study proposes a stage-gate integrated risk control framework focusing on the design phase of international LNG plant projects. An improved process to identify and analyze risks using the source-event, risk path, and quantification using probability-impact-significance of coordination concept are incorporated. A total of 83 risk factors of the design phase are identified and their quantification, prioritization, mitigation and monitoring methods are proposed along a state-gate framework. An illustrative case application is conducted to a real LNG plant project and its distinct benefits to manage and control risks of LNG projects are validated. Applicability and usability of the framework is also tested. The proposed framework is expected to function as effective tools for minimizing the risk of LNG projects and maximizing the management capacity of practitioners.

In construction projects, the different interests and objects of stakeholders can result in increased occurrences of conflict, which can bring negative effects or even project termination. In particular, understanding the causes and finding a solution get more difficult because of the larger and more complex projects. Thus, quantitative research should be conducted to find conflict alternatives. This study aims to find optimal alternative combinations for conflict resolution in public projects. To understand level of conflict and effect of conflict alternatives, the survey was conducted in three points of view: 1) economic; 2) social; and 3) environmental. After survey, the optimization process consists of two steps. First, weights of conflict factors are estimated through regression analysis. Second, multi-object functions which are each economic impact, social impact, environmental impact are optimized. For multi-objective optimization, optimal alternative combinations could be deducted and results present how alternatives affect to conflict level. Although there are some limitations, this result is significant in that it has found an optimal alternative considering three impacts in order to select a combination of alternatives for conflict resolution.

An important issue for international businesses and academia is selecting countries in which to expand in order to achieve entrepreneurial sustainability. This study develops a country selection model for sustainable construction businesses using both objective and subjective information. The objective information consists of 14 variables related to country risk and project performance in 32 countries over 25 years. This hybrid model applies subjective weighting from industrial experts to objective information using a fuzzy LinPreRa-based Analytic Hierarchy Process. The hybrid model yields a more accurate country selection compared to a purely objective information-based model in experienced countries. Interestingly, the hybrid model provides some different predictions with only subjective opinions in unexperienced countries, which implies that expert opinion is not always reliable. In addition, feedback from five experts in top international companies is used to validate the model’s completeness, effectiveness, generality, and applicability. The model is expected to aid decision makers in selecting better candidate countries that lead to sustainable business success.

Since 1960’s, international construction market have explosively increase and have reached up to 600 Bil. US$ through active participation of construction firms and steady support of government. Nevertheless, owners, clients and financial institutions required reasonable criteria to effectively assess the overseas business capabilities of construction firms. However, the existing methods for construction firms rarely consi ders the perspective of overseas business capabil ities. To overcome these pr oblems, this study p roposes an evaluation system for overseas business capabilities of construction firms. First, the needs for new evaluation system is derived through FGI, and the direction of new evaluation system is presented by reviewing the limitations of existing methods. Also, the capabilities that are required for the performances for overseas businesses were analyzed through expert interviews. Finally, 3 1 primary evaluation indices consisting of 3 criteria - appropriateness of index, possibility of quantification, possibility of data gathering - are derived under 9 categories and 3 perspectives through surveys and consultation meeting. The preliminary investigation of 24 Kor ean construction firms are conducted for comparing the existing evaluation systems and to verify its applicability. The proposed method could provide a rational criterion to evaluate the construction firms, improve internal capacity of firms, and ultimately supports the success of the construction industry.Key words : International construction, Overseas business capability, Evaluation of construction firm, Evaluation index초 록해외건설 시장은 건설기업들의 적극적인 참여와 정부의 지원 아래 괄목할만한 성장을 해왔으며 , 해외진출 50여년 만에 6000억 불 수주를 돌파하였다. 이러한 양적인 성장에도 불구하고 해외건설기업에 대한 명확한 평가기준의 부재로 인해 정부 및 유관기관에서는 지원 대상 및 주요 사업자 선정이 어려웠으며, 해외 발주자들의 건설기업 평가자료 요구에도 적극적으로 대응하기 어려웠다. 더욱이 건설기업들 조차도 자사의 해외공사 수행능력에 대한 판단이 미흡하여 합리적인 해외진출 의사결정이 부족하였다. 이에 본 연구는 해외건설능력 평가에 대한 필요성을 확인하였으며, 현행 평가체계 및 관련 연구를 분석하여 새로운 평가체계의 개발방향을 제시하였다 . 해외건설에 필요한 기업의 능력을 총 15회의 인터뷰를 통해 해외 발주자·대기업·중견기업의 관점 별로 분석하고, 설문 및 자문을 통해 평가 항목의 적절성, 계량화 가능성, 자료 획득 가능성의 세 가지 기준을 충족하는 31개 주요 평가지표를 도출하였다. 이후 국내 건설기업 24개 업체에 대한 검증을 실시하여 적용 가능성을 검토 받았다 . 본 연구에서 제시된 평가체계는 기존 평가 제도의 단점을 보완하여 해외건설능력 평가 기준의 명확화를 통한 적격 업체 선정에 도움이 될 뿐만 아니라, 결과적으로 기업 자신들의 내부역량을 향상시킴으로써 해외건설 산업의 전반적인 발전을 가져다 줄 것이라 기대된다 .검색어 : 해외건설, 해외건설 수행능력, 건설기업 평가, 평가지표 Construction Management

Construction firms have long attempted to forecast a project cash flow at the initial stage of a project, which is closely related to the payment conditions and financing schedules. There are, however, diverse risk factors influencing project cash flow, in particular for the domain of international projects, which often fluctuate because of a myriad of external as well as internal uncertainties. In this research, risk factors that impact the soundness of cash flow are classified into two categories: financial risks and project-specific risks. The former refers to the external economic conditions such as exchange rate, cost escalation, and interest rate which can be analyzed through a probabilistic financial algorithm. Then, the project-specific risks such as host country’s geotechnical conditions, weather and climate differences, and resource delivery conditions are further assessed through utility curves to represent the firm’s unique risk perceptions and thresholds to the amount of risk exposures. Results of cash flow forecasts by the proposed approach are compared with the actual cash flow of a retrospective case project. It is found that construction firms better decide on a decent level of cash contingency and the probable net-profit at completion by the adoption of the proposed approach.

The body of knowledge in decision making about international construction market entry has been primarily focused on identifying risk factors, quantifying risks, and developing risk management strategies for construction firms to be more likely to succeed in international markets (e.g., risk registrars, industry checklists, entry procedures, and quantitative/qualitative risk assessment models). Going international can also be considered as a large-scale investment for a firm because it has all three major characteristics of an investment decision: (1) entering an international market requires a substantial level of initial outlays; (2) this initial capital is not completely recoverable if the firm decides to exit the market; and (3) the success of an international construction business venture is subject to great market uncertainty, which is exogenous to the firm. Traditionally, financial valuation of international construction markets is conducted by net present value (NPV) analysis approach. Alt...

This study suggests a formalized method to quantitatively assess the performance of construction Research and Development (R&D) projects. The procedures for the method development starts with identifying 40 performance measurement indicators reflecting the characteristics of construction processes, based on a literature review and expert opinions. Then, a case survey is conducted to obtain the quantitative performance results of 355 completed R&D projects. Finally, baseline values measured on the relative statistics for each indicator are used to discern which construction R&D project performed well. ANOVA (Analysis of Variance) test is also applied to the R&D project data to show that the proposed method is applicable and valid. The proposed method is expected to quantitatively evaluate R&D outputs for determining which projects deserve reward or more funding on the priority of R&D investments.

We propose and experimentally demonstrate an optical millimeter-wave and sub-terahertz signal generation method based on frequency 18-tupling using a power amplifier, an optical modulator, and a semiconductor optical amplifier (SOA). The power amplifier is operated in the nonlinear region and generates a third-order harmonic frequency. Next, frequency doubling by optical carrier suppression using the optical modulator is performed. Four-wave mixing of the SOA and optical filtering produce two-tone waves whose frequency spacing corresponds to 18-tupling of the input RF frequency. The experimental results show that two idlers could be obtained at 1549.98 and 1550.85 nm in the wavelength domain corresponding to the beat frequency of 108 GHz from the 6 GHz RF signal. Because of the bandwidth limitations of our available photodetectors, the phase noise of the beat signal is measured at a lower frequency of 60 GHz for the input of 3.3 GHz and is −74.60 dBc/Hz at an offset of 100 kHz. © 2013 Wiley Periodicals, Inc. Microwave Opt Technol Lett 55:1677–1680, 2013; View this article online at wileyonlinelibrary.com. DOI 10.1002/mop.27605

In the recent global construction environment, EPC contracts that integrate planning, design, procurement, and construction have been widely used for industrial facilities. Similarly, as the importance of the engineering capability such as project management consulting(PMC) and front end engineering design(FEED) has been increased, design-build contracts also have been gradually adopted for infrastructure projects. Whereas, the Korean infrastructure industry has fragmentary features which mainly emphasize on the construction sector. Therefore, this study aims at developing strategies for enhancing the engineering capability and for balancing the competitiveness between engineering and construction sectors in the Korean infrastructure industry. To this end, the authors first carried out market analysis for both global and domestic market. Then, a structured survey and expert in-depth interviews were sequentially performed in order to reflect practitioners` perspectives and needs for institutional strategies. As a result, five strategies drawn from this study are as follows: 1) rearranging the government`s roles for supporting the engineering sector; 2) establishing institutional bases being compatible with global standards; 3) fostering value-added workforce for undertaking complex tasks; 4) constructing an consortium between an engineering association and general contractors; and 5) building a nationwide collaborative networks for overseas market expansion.

Global market uncertainties such as unpredicted recession and recovery arise simultaneously at the country level or wider. These uncertainties weaken traditional project-based risk management to control contractors’ revenue and return. To overcome this limitation, this study suggests a country portfolio model for managing these market uncertainties. This model presents the quantitative diversification strategy that optimizes country portfolio solutions through considering four critical objectives at the country level: (1) market growth rate, (2) market growth volatility, (3) market profit rate, and (4) market profit uncertainty. This study applies Markowitz portfolio theory to this country portfolio solution and uses multiobjective genetic analysis (MOGA) through examining 1,014 international projects executed by Korean contractors across 21 countries. This study suggests three useful applications: (1) analysis of the ideal country portfolio, (2) evaluation of the firm’s current portfolio associat...