• Journal of Convergence for Information Technology
• /
• v.9 no.1
• /
• pp.19-27
• /
• 2019

In recent years, with the advancement of IT technology, we expect data size of the world to increase 10 times in 2025. The rapid development of this Internet technology leads to the downsizing of the server system of the data center which manages and operates the data, the capacity of the storage medium, and the power consumption of the data center. In this paper, we propose an energy conservation policy and analyze it in real time by analyzing the power consumption pattern of the server system of the data center. The proposed system can monitor and analyze the power consumption pattern of the individual server system in the data center, and it can be expected that about 10% of the total power consumption of the data center will be saved by efficiently managing the actual operation time of the server system.

• Nuclear Engineering and Technology
• /
• v.51 no.4
• /
• pp.987-995
• /
• 2019

Steam jet condensation is of great importance to pressure suppression containment and automatic depressurization system in nuclear power plant. In this paper, the condensation processes of sonic steam jet in a quiescent subcooled pool are recorded and analyzed, more precise understanding are got in direct contact condensation. Experiments are conducted at atmospheric pressure, and the steam is injected into the subcooled water pool through a vertical nozzle with the inner diameter of 10 mm, water temperature in the range of $25-60^{\circ}C$ and mass velocity in the range of $320-1080kg/m^2s$. Richardson number is calculated based on the conservation of momentum for single water jet and its values are in the range of 0.16-2.67. There is no thermal stratification observed in the water pool. Four condensation regimes are observed, including condensation oscillation, contraction, expansion-contraction and double expansion-contraction shapes. A condensation regime map is present based on steam mass velocity and water temperature. The dimensionless steam plume length increase with the increase of steam mass velocity and water temperature, and its values are in the range of 1.4-9.0. Condensation heat transfer coefficient decreases with the increase of steam mass velocity and water temperature, and its values are in the range of $1.44-3.65MW/m^2^{\circ}C$. New more accurate semi-empirical correlations for prediction of the dimensionless steam plume length and condensation heat transfer coefficient are proposed respectively. The discrepancy of predicted plume length is within ${\pm}10%$ for present experimental results and ${\pm}25%$ for previous researchers. The discrepancy of predicted condensation heat transfer coefficient is with ${\pm}12%$.

• Journal of the Korean Society of Marine Environment & Safety
• /
• v.25 no.1
• /
• pp.117-121
• /
• 2019

In this study, research and a demonstration for applying DC distribution systems to ships as an environmental and energy conservation solution in domestic and foreign countries were actively carried out. In order to apply a generator to a DC distribution system, a variable speed engine was used. Both engine speed and fuel consumption were reduced. In this paper, a DC generator for DC distribution was constructed using a diesel generator, a generator controller, a governor, and an AVR. A system configuration method for a generator, power quality test, and the power characteristics of a variable speed generator were analyzed. The voltage (250 - 440 VAC) and frequency (34 - 60 Hz) of the variable speed generator were set to 60 - 100 % of the rated value, and the engine was set to operate from 1100 - 1800 rpm. It was confirmed that the voltage, current, and frequency of the generator output fluctuated in a stable manner according to the power amount when changing the engine speed of the generator according to the load variation.

• The Journal of the Convergence on Culture Technology
• /
• v.5 no.3
• /
• pp.251-256
• /
• 2019

With the fast development of modern society, the interests concerned about the significance of nature and environment become major issue nowadays. Especially, threats for our health due to severe environmental pollution and fine dusts become serious problem with the fast industrialization of our society, and extra attention is focused on interests about conservation of nature and management of forest resources. Precious forest resources, however, are not properly managed and destroyed vainly due to frequent fire, damage by storms and floods, and unplanned land development. So systematic and scientific construction and management of forest resources are required in order to solve these problems efficiently. Furthermore, implementation of the forest resource information database that contains information of trees, Topography, ecosystem of the forest is urgently needed. In this paper, we design and implement the forest resource information database based on the information of location based forest resources and Topography using forest images taken by a drone, that enables us to manage forest resources efficiently, make decision for logging, and construct a future tree-planting project easily.

• Journal of the Korea Convergence Society
• /
• v.12 no.2
• /
• pp.7-13
• /
• 2021

This paper introduces an algorithm that compensates for missing values after converting them into a format that can represent the probability for incomplete data including missing values in training data. In the previous method using this data conversion, incomplete data was processed by allocating missing values with an equal probability that missing variables can have. This method applied to many problems and obtained good results, but it was pointed out that there is a loss of information in that all information remaining in the missing variable is ignored and a new value is assigned. On the other hand, in the new proposed method, only complete information not including missing values is input into the well-known classification algorithm (C4.5), and the decision tree is constructed during learning. Then, the probability of the missing value is obtained from this decision tree and assigned as an estimated value of the missing variable. That is, some lost information is recovered using a lot of information that has not been lost from incomplete learning data.

• The Journal of the Korea Contents Association
• /
• v.21 no.4
• /
• pp.434-446
• /
• 2021

Recently, there has been a growing interest in the fourth industrial revolution, expected to have a significant impact on society. However, there are only a few studies on spatial distribution and location of the fourth industry. This study tried to classify the spatial distribution of the fourth industry by using LQ, a non-geographical method, and Getis-Ord's Gi^*, a geographical method. The results of the analysis are as follows. First, there are the specialized areas of the fourth industry in the non-Seoul metropolitan area as well as the Seoul metropolitan area. Second, industrial clusters and neighborhood areas of the fourth industry were located mostly in the Seoul metropolitan area. Third, industrial clusters were concentrated on the southern part of Gyeonggi Province and Seoul, and there are no industrial clusters in the northern part of the Seoul metropolitan area and the nature conservation area. This paper shows that the cluster area of the fourth industry is concentrated in the Seoul metropolitan area. Therefore, policies for the 4th industry are needed to solve this unbalanced spatial distribution of the fourth industry.

• Journal of Korean Society on Water Environment
• /
• v.38 no.5
• /
• pp.240-246
• /
• 2022

Water and energy are inextricably linked and referred to as 'Water-Energy Nexus'. Recently, this topic has been drawing a lot of attention from various studies due to the exacerbated water availability. Korea's water and energy consumption has been increasing consistently, which calls for better management. This paper aims to identify changes in electricity consumption in relation to water intake and purification processes. Using Log Mean Divisia Index (LMDI) Decomposition Analysis method, this study attributes the changes to major factors such as; Total population (population effect), household/population (structure effect), GDP/household (economic effect), and water-related energy use/GDP (unit effect). The population effect, structure effect, and economic effect contributed to an increase in water-related electricity consumption, while the unit effect contributed to a decrease. As of 2019, the economic effect increased the water supply sector's electricity consumption by 534 GWh, the population effect increased by 73 GWh, and the structure effect increased by 243 GWh. In contrast, the unit effect decreased the electricity consumption by -461 GWh. We would like to make the following suggestions based on the findings of this study; first, the unit effect must be improved by increasing the energy efficiency of water intake and purification plants and installing renewable energy power generation facilities. Second, the structure effect is expected to increase over time, and to mitigate it, water consumption must be reduced through water conservation policies and the improvement of water facilities. Finally, the findings of this study are expected to be used as foundational data for integrated water and energy management.

• Nuclear Engineering and Technology
• /
• v.54 no.10
• /
• pp.3745-3765
• /
• 2022

The concrete structures related to nuclear safety are threatened by accidental impact loadings, mainly including the low-velocity drop-weight impact (e.g., spent fuel cask and assembly, etc. with the velocity less than 20 m/s) and high-speed projectile impact (e.g., steel pipe, valve, turbine bucket, etc. with the velocity higher than 20 m/s), while the existing studies are still limited in the impact resistant design of nuclear power plant (NPP), especially the primary RC slab. This paper aims to propose the numerical simulation and theoretical approaches to assist the impact-resistant design of RC slab in NPP. Firstly, the continuous surface cap (CSC) model parameters for concrete with the compressive strength of 20-70 MPa are fully calibrated and verified, and the refined numerical simulation approach is proposed. Secondly, the two-degree freedom (TDOF) model with considering the mutual effect of flexural and shear resistance of RC slab are developed. Furthermore, based on the low-velocity drop hammer tests and high-speed soft/hard projectile impact tests on RC slabs, the adopted numerical simulation and TDOF model approaches are fully validated by the flexural and punching shear damage, deflection, and impact force time-histories of RC slabs. Finally, as for the two low-velocity impact scenarios, the design procedure of RC slab based on TDOF model is validated and recommended. Meanwhile, as for the four actual high-speed impact scenarios, the impact-resistant design specification in Chinese code NB/T 20012-2019 is evaluated, the over conservation of which is found, and the proposed numerical approach is recommended. The present work could beneficially guide the impact-resistant design and safety assessment of NPPs against the accidental impact loadings.

• The Journal of Fisheries Business Administration
• /
• v.53 no.3
• /
• pp.43-64
• /
• 2022

Efforts to prevent IUU fishing began in 1996 as the IUU Antarctic Marine Living Resources Conservation Committee reported the multilateral efforts of the international community and related international organizations to prevent IUU fishing. Korea has recently been pointed out by the international community as to many problems regarding its will to eradicate IUU fishing. It is true that Korea has ever been designated as an 'IUU participating country' or a 'non-cooperative third country' by the international community and that there have been considerable difficulties in exporting seafood and using ports along with the deterioration of the national image. In 2020, with the efforts of related organizations and fisheries companies, Korea is now free from being known as a that Korea has recovered some degrees of trust from the international community through strengthening legal sanctions against IUU fishing and thorough implementation of follow-up measures is now free from non-cooperating country it cannot be said that the basic problems have been completely resolved just because it has emerged as a disgraceful country, and the current state of IUU fishing of Korea leaves a room for designation as a 'non-cooperative third country' again at any time in the future. Accordingly, there is an urgent need to examine the problems of the IUU fishing-related legal system in Korea and to come up with an improvement plan. Therefore, this paper reviews international norms for IUU fishing regulation (PSMA etc.) and domestic laws with the Distant Water Fisheries Development Act and Propose the improvement methods for related legal systems in Korea.

• Journal of Intelligence and Information Systems
• /
• v.29 no.1
• /
• pp.215-231
• /
• 2023

Taking Pingjiang historical and cultural block in Suzhou as an example, this paper collects 1436 tourist comment data from Ctrip. com with Python technology, and uses network text analysis method to analyze frequency words, semantic network and emotion, so as to evaluate the tourist perception characteristics and levels of the Grand Canal cultural heritage. The study found that: natural and humanistic landscapes, historical and cultural deposits, and the style of the Jiangnan Canal are fully reflected in the perception of visitors to the Pingjiang Historical and Cultural District; Tourists hold strong positive emotions towards the Pingjiang Road historical and cultural district, however, there is still more space for the transformation and upgrading of the district. Finally,suggestions for measures to improve the perception of tourists of the Grand Canal cultural heritage are given in terms of conservation first, cultural integration and innovative utilization.