• The KIPS Transactions:PartA
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• v.13A no.3 s.100
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• pp.191-198
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• 2006

Today's portable electric consumer devices, which are operated by battery, tend to integrate more multimedia processing capabilities. In the multimedia processing devices, multimedia system-on-chips can handle specific algorithms which need intensive processing capabilities and significant power consumption. As a result, the power-efficiency of multimedia processing devices becomes important increasingly. In this paper, we propose a reconfigurable data caching architecture, in which data allocation is constrained by software support, and evaluate its performance and power efficiency. Comparing with conventional cache architectures, power consumption can be reduced significantly, while miss rate of the proposed architecture is very similar to that of the conventional caches. The reduction of power consumption for the reconfigurable data cache architecture shows 33.2%, 53.3%, and 70.4%, when compared with direct-mapped, 2-way, and 4-way caches respectively.

• Journal of the Korea Society of Computer and Information
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• v.25 no.6
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• pp.99-107
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• 2020

In this paper, we analyze the characteristics of mobile cache, which is used to improve the data access speed when executing applications on mobile devices, and verify the importance of mobile cache through a cache data access experiment. The mobile device market has grown at a fast pace over the past decade; however, battery limitations and size, price considerations restrict the usage of fast hardware. Thus, their performance are supplemented by using a memory buffer structure such as the cache memory. The analysis mainly focuses on cache size, hierarchical structure of cache, cache replacement policy, and the effect these features has on mobile performance. For the experimental data, we applied a data set from a microprocessor system study, originally used to test the cache performance. In the experimental results, the average data access speed on a mobile device showed a performance improvement of up to 10 times with the presence of cache memory than without. Accordingly, the cache memory was helpful for the performance improvement of a mobile device when the specifications were identical.

• Journal of Advanced Navigation Technology
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• v.26 no.5
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• pp.338-343
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• 2022

The Air Radio Station plays a role in creating skyways for aircraft and helping them fly safely through aviation mobile communication facilities (U/VHF transceivers) and various navigation safety facilities. It is necessary to remove large trees and weeds around the aircraft because accurate and safe signals must be provided without interruption. During the mowing work for the efficient management of landscaping facilities, there have been cases in which noise is introduced by Lawn Mower, which hinders control work. Accordingly, in order to analyze how mower affects air mobile communication facilities, the interference effect on air mobile communication facilities was analyzed for four types of mower, two-stroke, and battery type. As a result of the analysis, it was found that the two-stroke mower greatly affects air mobile communication facilities.

• Journal of the Korea Institute of Building Construction
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• v.11 no.3
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• pp.283-291
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• 2011

As the construction industry has recently been transformed by the emergence of ubiquitous and intelligent technology, there have been major changes in the management methods employed. Specifically, next-generation construction management systems have been developed that collect and analyze many pieces of information in real time by using various wireless sensors and networks. The purpose of this study is to understand the current status of Ubiquitous Sensor Networks (USN) in the construction sector, and to gain fundamental data for a system of measuring concrete curing temperature in a construction site that employs a USN. By investigating the application status of USN, it was confirmed that USN has mainly been applied to the maintenance of facilities, safety management, and quality control. In addition, a field experiment in which the curing temperature of concrete was measured using a USN was carried out to evaluate two systems with wireless sensor networks, and the applicability of these systems on site was confirmed. However, it is estimated that the embedded wireless sensor type is affected by metal equipment on site, internal battery of sensor and concrete depth, and studies to provide more stable system by USN are thus required.

• Journal of Preventive Medicine and Public Health
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• v.31 no.4 s.63
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• pp.728-739
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• 1998

To improve wellness and quality of life by recognizing the health efforts of stress, the author estimated the relationships between stress, subjective symptoms and clinical diagnosis through a questionnaire and a battery of specified laboratory tests; electrocardiography, blood pressure, cholesterol, aspartate aminotransferase(AST), alanine aminotransferase(ALT), gamma glutamyl transferase$(\gamma-GTP)$, fasting blood sugar, gastro-endoscopy or UGI, abdominal sonography, etc. The data was gathered from 337 clients who were undergoing multiphasic screening program at a University Hospital from January to March 1998. The mean age of subjects was $46.5{\pm}11.2$ years and the mean of body mass index was $24.0{\pm}3.7kg/m^2$. The mean vol of stress was $18.5{\pm}6.0$ expressed as the score out of 40. By general characteristics and lift style among male, mean level of stress was significantly higher in case of lower socioeconomic status, habitual drug use, longer daily working time(>10 hours), no regular exercise, drinkers, irregular meal, skip-ping breakfast(p<0.05). In case of female, that was significantly higher in case of lower education, lowe. socioeconomic status, longer daily working time(>10 hours), no regular exercise, drinkers, smokers, irregular meal, skipping breakfast(p<0.05). Significant correlations were observed between stress and subjective symptoms in all kinds of organ system (p<0.01). Correlation coefficients of stress among male were relatively high with neuro-psychiatric symptom$(\gamma=0.476)$ and cardio-vascular symptom$(\gamma=0.361)$ in order, and correlation coefficients of stress among female was highest with neuro-psychiatric symptom$(\gamma=0.371)$. The prevalence of the diagnosis through the battery of laboratory tests was high in upper gastrointestinal disorders and hypercholesterolemia in order in both sex group. Among male the mean score of stress was significantly high in ulcerative peptic disorder of upper gastrointestine and hepatopathy in order (p<0.05) . Among female that was significantly high in diabetes mellitus. In summary, it is likely that there are associations between stress, subjective symptoms and clinical diagnosis. To promote wellness and quality of life it would be of value that periodic stress evaluation program and stress management including apropriate control of smoking and drinking, regular exercise and meal.

• Fire Science and Engineering
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• v.34 no.2
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• pp.147-155
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• 2020

This paper presents a study on the development of a fire extinguishing agent and extinguishing system for an energy storage system (ESS) fire. The fire extinguishing agent designed to extinguish an ESS fire is a highly permeable fire extinguisher that reduces the surface tension and viscosity while bringing about cooling action. This is the main extinguishing effect of this type of wetting agent, which displays the characteristics of fire extinguishing agents used for penetrating the battery cells inside the ESS module. For the fire extinguishing system, a local application system was designed to suppress fire on a rack-by-rack basis. A 360° rotating nozzle was inserted into the rear hall of the ESS module, and general nozzles were installed in the rack to maximize the fire extinguishing effect. The fire extinguishing agent was strongly discharged by virtue of the gas release pressure. Experiments on fire suppression performance with ESS module 1 unit and module 3 units showed that all visible flames were extinguished in 8 s and 9 s, respectively, by the fire extinguishing agent. In addition, based on confirming reignition for 600 s after the fire extinguishing agent was exhausted, it was confirmed that the ESS fire was completely extinguished without reignition in all fire suppression performance experiments.

• Journal of the Korean Society of Marine Environment & Safety
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• v.28 no.6
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• pp.1086-1091
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• 2022

The International Maritime Organization is establishing international agreements on maritime safety and security to prepare for the introduction of autonomous ships. In Korea, the industry is focusing on autonomous navigation system technology development, and to reduce accidents involving coastal ships, research on autonomous ship technology application plans for coastal ships is in progress. Interest in autonomously operated ships is increasing worldwide, and maritime demonstrations for verification of developed technologies are being pursued. In this study, a basic investigation was conducted on the design of a demonstration ship and an onshore platform (remote support center) using digital twin technology for application to coastal ships. To apply digital twin technology, an 8-m small battery-powered electric propulsion ship was selected as the target. The basic design of the twin-integrated platform was developed. The ship navigation and operation data were stored on a server system, and remote-control commands of the electric propulsion ship was achieved through communication between the ship and the onshore platform. Ship performance management, operation and operation optimization, and predictive control are possible using this digital twin technology. This safe and economical digital twin technology is applicable to ships responding to crisis scenarios.

• Journal of Internet Computing and Services
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• v.23 no.5
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• pp.47-58
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• 2022

In recent years, navigation aids, which plays as sea traffic lights, have been digitized, and are developing beyond simple sign purpose to provide various functions such as marine information collection, supervision, control, etc. For example, Busan Port which is located in South Korea is leading the application of the advanced technologies by installing cameras on buoys and recording video images to supervise maritime accidents. However, there are difficulties to perform their major functions since the advanced technologies require long-term battery operation and also management and maintenance of them are hampered by marine characteristics. This study proposes a system that can automatically notify maritime objects passing around buoys by analyzing image information. In the existing sensor-based accident prevention systems, the alarms are generated by a collision detection sensor. The system can identify the cause of the accident whilst even though it is difficult not possible to fundamentally prevent the accidents. Therefore, in order to overcome these limitations, the proposed a maritime object detection system is based on marine characteristics. The experiments demonstrate that the proposed system shows about 5 times faster processing speed than other existing algorithms.

• Journal of KIISE:Computer Systems and Theory
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• v.35 no.11
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• pp.517-526
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• 2008

As the functionality of portable devices arc being enhanced and the performance is being greatly improved, power dissipations of battery driven portable devices are being increased. So, an efficient power management for reducing their power consumption is needed. In this paper, we propose a window-based DVS algorithm for MPEG Player. The proposed algorithm maintains the recently frame information and execution time received from MPEG player in window queue and dynamically adjusts (frequency, voltage) level based on window queue information. Our algorithm can be implemented in the common multimedia player as a module. We employed well-known MPlayer for the measurement of performance. The experimental result shows that the proposed algorithm reduces energy consumption by 56% on maximal performance.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.13 no.4
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• pp.774-784
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• 2009

A wireless sensor network consisting of a large number of nodes with limited battery power should minimize energy consumption at each node to prolong the network lifetime. To improve the sensitivity of wireless sensor networks, an efficient scheduling algorithm and energy management technology for minimizing the energy consumption at each node is desired. ill this paper, we propose energy-aware routing mechanism for maximum lifetime and to optimize the solution quality for sensor network maintenance and to relay node from its adjacent cluster heads according to the node"s residual energy and its distance to the base station. Proposed protocol may minimize the energy consumption at each node, thus prolong the lifetime of the system regardless of where the sink is located outside or inside the cluster. Simulation results of proposed scheme show that our mechanism balances the energy consumption well among all sensor nodes and achieves an obvious improvement on the network lifetime. To verify propriety using NS-2, proposed scheme constructs sensor networks adapt to current model and evaluate consumption of total energy, energy consumption of cluster head, average energy dissipation over varying network areas with HEED and LEACH-C.