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This paper proposes a novel cooperative control strategy for voltage restoration and power management in DC microgrids based on the DC bus signaling (DBS) method. In the conventional DBS method, the operation mode is determined according to the voltage deviation. Thus, it is difficult to achieve voltage restoration. To overcome this problem, the conventional DBS method is modified by applying the total power of dispatchable units (DUs) to identify the operation mode instead of the voltage deviation. As a result, the average output voltage of the DUs is restored to its nominal value in all of the operation modes without difficulty. In addition, accurate power sharing is achieved regardless of the line impedance or load change by regulating the voltage magnitude using a simple PI controller. Furthermore, the control performance is theoretically analyzed using a small signal analysis to evaluate the stability of system. The proposed method is validated with results from a lab scale experiment.

Accurate power sharing in a DC microgrid with a conventional distributed control scheme is impossible to achieve due to the heterogeneity of communication time delays. To address this problem, an anti-heterogeneous time delay estimator is proposed on the basis of scattering transformation and a PI consensus algorithm, and proper power allocation is achieved along with voltage compensation in a distributed fashion. In the proposed estimator, transmitted/received signals are modified via scattering transformation, and average consensus is estimated by the PI consensus algorithm. Consequently, proportional power sharing and voltage compensation are achieved concomitantly despite heterogeneous temporal delays, mismatched line resistances, and load variation. The effectiveness of the proposed method is evaluated through experiments.

Purpose Design-Build (D-B) is a project delivery method in which the owner procures both design and construction services in the same contract from a single legal entity. There is limited research on how communication among parties influences the success of D-B projects. The purpose of this paper is to examine D-B communication issues and provides effective practices on communication to improve D-B procurement processes in the USA. Design/methodology/approach The research methodology for this study includes a comprehensive review of literature, survey questionnaire, and structured interviews. A questionnaire was developed to collect data from professionals with an average of 23 years of experience related to D-B procurement. Eight structured interviews were conducted to verify and validate the survey questionnaire results. Findings The results showed that the communication issues vary along with each phase of the D-B process. The primary communication practices influencing the success of D-B projects are: establishing clear points of contact; providing clear and understandable information among stakeholders during the D-B process; and the timely sharing of information to all stakeholders. Research limitations/implications The chief limitation of this research is that the primary data were mostly opinions from experts although several empirical data were collected for cross-validation. This research did not consider the relationship of relevant contract clauses and communication issues. Practical implications The findings from this paper will help professionals better understand the D-B procurement process. Originality/value This is one of the first attempts to discuss D-B communication issues in each different phase of a D-B project.

Ionizing radiation (IR) treatment induces a DNA damage response, including cell cycle arrest, DNA repair, and apoptosis in metazoan somatic cells. Because little has been reported in germline cells, we performed a temporal analysis of the DNA damage response utilizing Drosophila oogenesis as a model system. Oogenesis in the adult Drosophila female begins with the generation of 16-cell cyst by four mitotic divisions of a cystoblast derived from the germline stem cells. We found that high-dose irradiation induced S and G2 arrests in these mitotically dividing germline cells in a grp/Chk1- and mnk/Chk2-dependent manner. However, the upstream kinase mei-41, Drosophila ATR ortholog, was required for the S-phase checkpoint but not for the G2 arrest. As in somatic cells, mnk/Chk2 and dp53 were required for the major cell death observed in early oogenesis when oocyte selection and meiotic recombination occurs. Similar to the unscheduled DNA double-strand breaks (DSBs) generated from defective repair during meiotic recombination, IR-induced DSBs produced developmental defects affecting the spherical morphology of meiotic chromosomes and dorsal-ventral patterning. Moreover, various morphological abnormalities in the ovary were detected after irradiation. Most of the IR-induced defects observed in oogenesis were reversible and were restored between 24 and 96 h after irradiation. These defects in oogenesis severely reduced daily egg production and the hatch rate of the embryos of irradiated female. In summary, irradiated germline cells induced DSBs, cell cycle arrest, apoptosis, and developmental defects resulting in reduction of egg production and defective embryogenesis.

Large construction projects are inherently complex and dynamic. A comprehensive answer on how to manage such projects successfully is difficult to provide. This paper expounds on the success factors for large construction projects in Vietnam. A survey questionnaire was used to collect data from practitioners. Factor analysis was employed to categorize these success factors perceived by 109 respondents from 42 construction-related organizations. Factor analysis uncovered that these success factors can be grouped under four categories, here titled the four COMs: comfort, competence, commitment, and communication. The result can be used as a guideline to successfully handle construction projects in Vietnam as well as in other countries, especially in the emerging economies in Asia and the rest of the world.

This study aims to determine the factors from social media and crowd psychology among individuals, a group, or communities on social networks that affect the attitudes of Lesbian, Gay, Bisexual, and Transgender (LGBT) students at FPT University in Ho Chi Minh City toward coming out to their parents. The research desires to determine whether there is any difference in terms of year of admission, major, and the frequency of social media use. The research method is quantitative research (survey - using questionnaire). The sample size of the survey is 154 LGBT students; All respondents are studying at FPT University Ho Chi Minh City. The results showed that searching for information and digital coming out are the two factors that have the most substantial impact on the attitudes of LGBT students at FPT University in Ho Chi Minh City (HCMC) towards disclosing their sexual orientation to their parents.

Project management knowledge areas such as cost estimating, financial evaluations and project planning tend to receive less focus in engineering curricula. Students often perceive them not as “core” knowledge in their engineering majors. Increasing engineering student interest, attention, engagement and deeper learning in these knowledge areas is a challenge. In addition to making course materials relevant to these engineering disciplines, instructors have to employ various active learning initiatives to ensure effective teaching and learning are actually taking place. This paper presents a case study of using a poll app called Poll Everywhere as an active learning activity in a required senior-level “engineering project management” course for civil and environmental engineering students. As a question driven and student active tool, the poll app was used to quickly assess the students’ learning in a previous lesson. The responses were optional and not graded in order to stimulate discussion among small groups of students when working on the poll questions. The classroom setting that followed the SCALE‐UP (student-centered active learning environment for undergraduate programs) model was appropriate for such collaborative learning. The student interest, understanding and knowledge of the course content were perceived to improve among students taking classes that used the polling system compared to those taking in “control” classes that did not use this cloud-based response system. Both students and faculty recognized the benefits of this implementation for identifying knowledge gaps of the course content, having extra practice with collaborative learning and making class sessions more interactive. Polling the right questions and time management were among the challenges when implementing the system.

This study continues the work by the authors to investigate the efficacy of homework in an engineering mechanics (Statics & Dynamics) course, starting with data from the fall semester of 2013. Throughout this study we have investigated: hand-written solutions, frequent quizzes based on homework problems, and the Pearson Mastering Engineering software. Thus far variations in homework systems have had only minimal impacts on the student’s overall performance in the class, as assessed by performance on exam scores. In this paper authors will present the impact of utilizing the “adaptive follow-up” modules in Pearson Mastering Engineering, as well as a reflection on the different methods used over the study period. As in previous years, assessment of the efficacy of homework assignments will be based on observation of students’ performance on exams, and a survey of students’ perceptions relative to historical norms. Institutional review of research protocol determined that full board review of the study and informed consent was not required.

Delay claims in construction projects present various tough and controversial issues. How to prove the three elements, namely entitlement, causation, and quantum in the \"triad of proof\" is an onerous task. The analyses of schedule delays and their associated damages especially concern claims analysts, project parties, courts, Boards of Contract Appeals, and so forth. On the one hand, the industry has employed various forensic schedule analysis techniques to support delay claims. Paradoxically, schedule-related factors such as float, logic, and resource allocation are frequently ignored even though they can affect project completion time and delay responsibility, too. On the other hand, the current 'one-size-fits-all' methods for calculating financial consequences undermine the relative importance of delayed activities and the fluctuating nature of overhead levels. The effects of the context of a delay in terns of the timing of the delay and decree of suspension should be therefore paid attention in quantifying delay damages. Accordingly, this research develops novel techniques for analyzing causation and calculating damages in construction delay claims. They address the dynamics of (loan, logic, resource allocation and the delay context in forensic schedule analysis and delay claims. Several published and hypothesized case studies are used to illustrate their applications. Among other things, this research proposes: (1) an enhanced window analysis technique considering resource allocation; (2) an activity-specific overhead allocation process (ASAP) for quantifying field-overhead damages; (3) FLORA as a novel forensic schedule analysis technique that can capture the dynamics of float, logic, and resource allocation; and (4) a framework which integrates FLORA and ASAP for analyzing schedule delays and their field overhead damages in a real-time and interactive manner. Through the applications, comparisons, and evaluations in case studies, these developments really overcome various limitations of the available techniques and practices currently used in forensic scheduling and delay claims. This research recommends that the schedule-related factors should be captured in forensic schedule analysis. In addition, the quantification of delay damages should emphasize the context of a delay. This also enables equitable apportionments when concurrent delays occur. ASAP and FLORA developed in this research are able to tackle these issues.

Extensive literature indicates that industry involvement in capstone design courses provides benefits to students, faculty, and industry practitioners. This paper presents the civil and environmental engineering senior design curricula at AAA University and the contributions of industry participants to student experiential learning. Practitioners have been involved in various roles, including project mentors for capstone design projects and/or judges for students’ capstone design project presentations. This paper provides course assessment and student feedback regarding the multiple aspects of the capstone design course. Practitioners, through the students, are provided by new ways of looking at and solving problems. Practitioners, through their involvement, provide valuable feedback to the faculty and students that enriches the overall experience gained in the capstone design course. This feedback helps improve student performance on their project and provides them with additional tools to carry forward to their engineering careers. A survey was conducted to obtain insights into the contributions of industry involvement in the capstone design course from the perspective of practitioners. This paper reports the results of this survey and describes two successful projects.