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Consistently updating, analyzing, and managing construction-related information is one of the key success factors in project management. Quite a few construction projects have recently started to utilize instant messaging (IM) applications such as Slack, WhatsApp, and WeChat as a communication channel among project participants to share daily construction information due to easy accessibility. However, general contractors are still required to manually extract and integrate the data from instant messages to compose daily reports. This is because the data inputted by subcontractors through IM applications are usually in an unstructured form and the IM application is not normally interoperable with the systems database especially developed for construction management. To solve this problem, this study proposes a chatbot-assisted construction daily report data management system. The chatbot in the proposed system collects and processes the required information through conversations with subcontractors, and automatically generates and shares a daily report for general contractors. A prototype system has been designed and implemented to prove the concept.

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Previous studies on automated fire-egress guidance systems have focused on providing the shortest path information from a specific person at a certain point to the closest exit mostly using a mobile device. This study aims to develop a Smart Exit Sign system that can detect dangerous areas in real time and direct evacuees to the shortest safe evacuation path by dynamically changing the direction signs to the safe egress. The challenge was to provide the shortest safe egress to any evacuees at any point. We have developed a sensor network and algorithm that could exclude unsafe paths and calculate the shortest safe path from multiple starting points to multiple exit points based on Dijkstra's algorithm-the most commonly used algorithm for finding the shortest path. The validity of the proposed system was tested through simulations of test cases.

A smart exit-sign system is an exit-sign system that can proactively orient the direction of an exit sign toward the shortest safe path in fire situations. In a previous study, an automated direction setting algorithm for a smart exit sign was proposed that assumed the exit signs were controlled by the main central server. This study proposes a new direction setting algorithm for a server-independent smart exit-sign system. The server-independent direction setting algorithm (SIDSA) can be divided into four main steps once the smart exit-sign system is installed and initialized: (1) update of the fire-status information detected by a sensor; (2) sharing of the fire-status information with neighboring exit-sign modules; (3) update of the shortest-path (distance) information according to the fire situation; (4) update of the direction on the display board. SIDSA has been validated through multiple simulations.

This paper presents the factors that could potentially affect the reliability of a serverless smart exit sign system, namely an evacuation guidance system based on a wireless sensor network (WSN) without a central server. Serverless smart exit sign system dynamically changes the directions of signs to indicate the shortest safe evacuation paths. Thus, the reliability of these systems is critical. Nevertheless, no research has been conducted to test the reliability of serverless smart exit sign systems. As a first step, we conducted a literature review to analyze the factors that could degrade the network performance of serverless smart exit sign systems. The identified factors were grouped into three categories: physical obstacles, environmental factors, and WSN properties. We plan to develop a prototype of a serverless smart exit sign system and then to conduct experiments to validate the influence of these factors on its network performance.

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