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Abstract:For the shipbuilding industry worldwide, work-related accidents at the construction site have been a major concern. Workers at the shipyards are consistently exposed to dangerous environments and their intensity of work is quite high. Considering the complexity of the shipbuilding process, efficient communications between workers are essential in the workplace, but current communication methods, which mostly use wireless technologies, are sometimes limited by the structural blocks, creating shadow areas where the radio bands cannot reach. As a countermeasure, SUNCOM Co., Ltd in the Republic of Korea has developed the PLC-based communication system followed by establishing a test-bed facility in cooperation with SK Telecom Co., Ltd and the Hyundai Heavy Industries Co., Ltd. This system and applied technologies are expected to reduce accidents in the field and be applied for other industries having the same problem, providing an uninterrupted communication environment and safer working conditions. The solution adopted this time can provide mobile communication services inside the ship during shipbuilding, thereby enabling rapid processing of work reports and instructions and fast responses to disaster occurrence, contributing to improvements in work efficiency in shipbuilding yards and ensuring workers' safety.

The purpose of this study is to evaluate the temperature distribution, strength development, porosity, scanning electron microscopy observation, shrinkage, and surface properties of concrete in order to apply microwave heat curing to the precast method and to analyze the CO2 emissions and economic feasibility of microwave heat curing. The heating of a steel form by microwave heating enabled concrete to be efficiently cured at a temperature within a range of ±5 °C. After the curing, demolding strength could be cleared through the densification of the concrete by decreasing the porosity of the concrete. Microwave heat curing exhibited excellent performance compared to conventional steam curing in terms of efficient temperature control, occurrence of cracks due to shrinkage, surface condition of concrete after curing, economic efficiency, and CO2 emissions. However, verification and supplementation based on actual data are necessary so that environments applicable to the various sizes and shapes of forms can be prepared.

Abstract. In this paper, the Integrated Ship Area Network which is suitable for the old or special ships built prior to the implementation of e-Navigation regulation by designing the PLC-based NMEA2000 integrated Network technology using the Ship-PLC. Since the Ship-PLC communication basically provides the Ethernet communication which has been used to support RS232/ 422/485 communications, technological implementation of various convergent multimedia communication was possible. With the test bed results using proposed technology in an actual ship, we've provided the possibility of shipbuilding cost reduction following plant structure changes and their numbers through integration of ship's power lines and circuits.