• Korean Journal of Remote Sensing
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• v.40 no.1
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• pp.19-31
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• 2024

Ports are vital social infrastructures that significantly influence both people's lives and a country's economy. In South Korea, the aging of port infrastructure combined with the increased frequency of various natural disasters underscores the necessity of displacement monitoring for safety management of the port. In this study, the time-series displacements of Yeongilman Port and surrounding areas in Pohang, South Korea, were measured by applying Permanent Scatterer Interferometric Synthetic Aperture Radar (PSInSAR) to Sentinel-1 SAR images collected from the satellite's ascending (February 2017-July 2023) and descending (February 2017-December 2021) nodes, and the displacement associated with the 2017 Pohang earthquake in the port was analyzed. The southern (except the southernmost) and central parts of Yeongilman Port showed large displacements attributed to construction activities for about 10 months at the beginning of the observation period, and the coseismic displacement caused by the Pohang earthquake was up to 1.6 cm of the westward horizontal motion and 0.5 cm of subsidence. However, little coseismic displacement was observed in the southernmost part of the port, where reclamation was completed last, and in the northern part of the oldest port. This represents that the weaker the consolidation of the reclaimed soil in the port, the more vulnerable it is to earthquakes, and that if the soil is very weakly consolidated due to ongoing reclamation, it would not be significantly affected by earthquakes. Summer subsidence and winter uplift of about 1 cm have been repeatedly observed every year in the entire area of Yeongilman Port, which is attributed to volume changes in the reclaimed soil due to temperature changes. The ground of the 1st and 2nd General Industrial Complexes adjacent to Yeongilman Port subsided during the observation period, and the rate of subsidence was faster in the 1st Industrial Complex. The 1st Industrial Complex was observed to have a westward horizontal displacement of 3 mm and a subsidence of 6 mm as the coseismic displacement of the Pohang earthquake, while the 2nd Industrial Complex was analyzed to have been little affected by the earthquake. The results of this study allowed us to identify the time-series displacement characteristics of Yeongilman Port and understand the impact of earthquakes on the stability of a port built by coastal reclamation.

• Journal of Venture Innovation
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• v.4 no.2
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• pp.97-108
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• 2021

Labor contracts appear in form as an exchange relationship between labor products and wages, but since they transcend the level of simple barter, they can be economically identified as "trading" and can be identified as "rental." From a legal point of view, a legal device that legally supports and imposes binding force on commodity exchange relations is a contract. Such a labor contract led to a relationship in which wages were received and a certain amount of time was placed under the direction and supervision of the employer as a counter benefit to the receipt of wages. Since working hours are subordinate hours with one's labor under the disposition authority of the employer, long hours of work can be done for the health and safety of workers and furthermore, it can be an act that violates the value to enjoy as a human being. The reduction of working hours needs to be shortened in terms of productivity and enjoyment of workers' culture so that they can expand and reproduce, but users' corporate management labor and production activities should also be compatible compared to those pursued by capitalist countries. Working hours can be seen as individual time and time in society as a whole, and long hours of work at the individual level are reduced, which is undesirable at the individual level, but an increase in products due to an increase in production time at the social level can help social development. It is necessary to consider working hours in terms of finding the balance between these individual and social levels. If the regulation method of working hours was to regulate the total amount of working hours, flexibility and elasticity of working hours are a qualitative regulation method that allows companies to flexibly allocate and organize working hours within a certain range of up to 52 hours per week. Accordingly, it is necessary to shorten working hours, but expand and implement the flexible working hours system according to the situation of the company. To this end, it is necessary to flexibly operate the flexible working hours system, which is currently limited to six months, handle the selective working hours by agreement between employers and workers, and expand the target work of discretionary working hours according to the development of information and communication technology and new types based on the 4th industrial revolution.