• The Journal of Korean Institute of Communications and Information Sciences
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• v.36 no.7A
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• pp.669-677
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• 2011

Superframe in IEEE 802.15.4 Standard is subdivided into an active period and an inactive period to reduce energy consumption. But communication nodes use same data transmission range in an active period, thus communication nodes spend a lot of energy to send data another nodes. In this paper, we proposed reduce energy consumption algorithm that nodes use different transmission power. Cordinator split transmission area into four group and transmit becon message to nodes. Nodes adjust transmission power according to becon message and wates lowe energy than normal nodes. We proposed energy-efficient cross layer protocol that have different PAN (Personal Area Network) by four range group.

• Journal of Korean Academy of Nursing Administration
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• v.6 no.1
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• pp.109-122
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• 2000

The present study examined the causal relationships among nurses' perceived autonomy, job satisfaction, work environment (work overload, role conflict, situational support, head nurses' leadership), personal aspects(experiences, need for achievement, professional knowledge and skill) by constructing and testing a theoretical framework. Based on literature review nurses' perceived autonomy and job satisfaction were conceived of as outcomes of the interplay among work environment and personal characteristics. Work environment factors involved work overload, role conflict, situational support, and head nurses' leadership (task oriented leadership, relation oriented leadership). Personal charateristics included experiences, need for achievement, and professional knowledge and skill. Three large general hospital in Chonbuk were selected to participate. The total sample of 516 registered nurses represents a response rate of 92 percent. Data for this study was collected from July to September in 1998 by Questionnaire. Path analyses with LISREL 7.16 program were used to test the fit of the proposed conceptual model to the data and to examine the causal relationship among variables. The result showed that both the proposed model and the modified model fit the data excellently. It needs to be notified, however, that path analisis can not count measurement errors; measurement error can attenuate estimates of coefficient and explanatory power. Nevertheless the model revealed relatively high explanatory power. 42 percent of nurses' perceived autonomy was explained by predicted variables; 32 percent of nurses' job satisfaction was explained by by predicted variables. Tn predicting nurses' perceived autonomy the findings of this study clearly demonstrated the work overload might be the most important variable of all the antecedent variables. Head nurses' relation oriented leadership, situational supports, need for achievement, and role conflict were also found to be important determinants for nurses' perceived autonomy. As for the job satisfaction, role conflict, situational supports, need for the achievement, and head nurses' relation oriented leadership were in turn important predictors. Unexpectedly the result showed perceived autonomy have few influence on job satisfaction. The results were discussed, including directions for the future research and practical implication drawn from the research were suggested.

• The Journal of the Korea institute of electronic communication sciences
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• v.15 no.3
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• pp.527-532
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• 2020

In this paper, we presented the results of analysis through EEG measurement for the purpose of checking the frequency band of EEG signals that can be used for personal authentication. The measurement status was divided into the open-eye state and the closed-eye state depending on the presence or absence of an optical task. The data measured in the EEG experiments was divided into seven frequency bands : delta waves, theta waves, alpha waves, SMR waves, mid-beta waves, beta waves and gamma waves to identify the frequency band with the smallest power fluctuation over time. In our results, there was no significant difference between the open-eye state and the closed-eye state, and the SMR waves and mid-beta waves related to human concentration had the smallest fluctuation in power over time, and were a highly reproducible frequency band.

• Journal of Environmental Health Sciences
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• v.41 no.4
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• pp.223-230
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• 2015

Objectives: There is considerable evidence that polluted ambient air contributes to the risk of cardiovascular morbidity and mortality. Heart rate variability (HRV) is defined as the variation in heartbeat intervals and has been reported as a biological marker of cardiovascular disease. This article reviews the existing literature in order to examine the association between air pollution and HRV. Methods: Literature was searched using Web of Science with the key words of "air pollution", "heart rate variability" and other related terms. A total of 156 articles were listed. For review, 21 of those listed publications were chosen after excluding studies regarding chamber studies, occupational environment, secondhand smoke and automobile exhaust. Results: Research methods employed in the publications were classified by type of participants (elderly/adult), air pollution monitoring (ambient/personal) and HRV monitoring (continuous/spot). Among HRV parameters, power in the low frequency range (LF), power in the high frequency range (HF) and standard deviation of all NN intervals (SDNN) were all associated with air pollutants. The chosen studies were mostly based on elderly populations. In studies based on continuous HRV monitoring, LF and SDNN significantly decreased when $PM_{2.5}$ exposure increased. Conclusion: Continuous HRV monitoring combined with personal exposure monitoring has been one of the most common study methods in recent publications. We expect that this review will be useful for the study of the association between air pollution and cardiovascular effects using HRV.

• Journal of Advanced Navigation Technology
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• v.23 no.4
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• pp.265-272
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• 2019

In this paper, we selected commuting scenarios in the most congested metropolitan area in Korea, and conducted noise analysis during personal air vehicle (PAV) operation using aviation environmental design tool (AEDT)software which was developed by Federal Aviation Administration (FAA). Noise is the second important factor after safety in order to operate PAVs through concepts such as ODM (on-demand mobility) introduced by National Aeronautics and Space Administration (NASA). Noise analysis were performed by modeling low-noise ePAVs as commercial helicopters and predicted residential suitability in order to resolve problems in which accurate NPD (noise power distance) data from PAVs were not released. The application of noise reduction technology such as electric propulsion has significantly reduced noise exposure levels and has reached the conclusion that commuting with PAVs is feasible without noise problems in the metropolitan area.

• Journal of information and communication convergence engineering
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• v.12 no.4
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• pp.252-256
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• 2014

Traditional block cipher Advanced Encryption Standard (AES) is widely used in the field of network security, but it has high overhead on each operation. In the 15th international workshop on information security applications, a novel lightweight and low-power encryption algorithm named low-power encryption algorithm (LEA) was released. This algorithm has certain useful features for hardware and software implementations, that is, simple addition, rotation, exclusive-or (ARX) operations, non-Substitute-BOX architecture, and 32-bit word size. In this study, we further improve the LEA encryptions for cloud computing. The Web-based implementations include JavaScript and assembly codes. Unlike normal implementation, JavaScript does not support unsigned integer and rotation operations; therefore, we present several techniques for resolving this issue. Furthermore, the proposed method yields a speed-optimized result and shows high performance enhancements. Each implementation is tested using various Web browsers, such as Google Chrome, Internet Explorer, and Mozilla Firefox, and on various devices including personal computers and mobile devices. These results extend the use of LEA encryption to any circumstance.

• 제어로봇시스템학회:학술대회논문집
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• 2001.10a
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• pp.138.6-138
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• 2001

In recent years, as the battery-powered portable systems such as cellular phone, personal digital assistant (PDA) are widely used, power consumption comes to be a top-priority design concerns. Because those embedded systems become more and more complex than ever and they are operated under severe power and energy constrains, long battery lifetime with a limited energy is very critical. Even though there are various levels of energy optimization techniques, system level techniques are mainly focused on, for their stronger impact on power consumption of the overall system than traditional techniques : circuit level, switch level, architecture level, etc. In this technique, operating system (OS) plays the most important role in the system because it controls ...

• 제어로봇시스템학회:학술대회논문집
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• 2002.10a
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• pp.79.6-79
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• 2002

We propose here sequential 2 methods for obtain information of current or potential data for power transmission line. One is a digital data transmission unit, this is, an output of a current sensor of power transmission line is digitalized by use of an easy asynchronous protocol. The unit has high speed transform rate, easy making header caused of consisting of only logic circuit. The other is, the output of the unit is transformed via LAN interface and displayed on a personal computer. We have confirmed remote measuring using the method for 100A and 240 A of the current information of power transmission line. Therefore we will be able to see a current waveform by use of internet at a cheep c...

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2008.06a
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• pp.184-184
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• 2008

In this paper, a power divider with a multi-band and broadband are designed and fabricated using an InGaP/GaAs process. The design of this divider is based on multi-band because it is important in the next generation IMT-Advances system. In this design, power divider is fabricated with the frequency of 824 MHz to 894 MHz, 1.8 GHz to 2.2 GHz and 2.3 GHz to 2.4 GH for cellular, personal communication system (PCS) and Wireless Broadband Internet (WiBro). The topology of the designed power divider is based on the multi-section and fabricated using integrated passive device (IPD) library of nanoENS Inc. It is measured using network analyzer.

• Proceedings of the SAREK Conference
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• 2008.11a
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• pp.95-98
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• 2008

A power line communications, power, the outgoing line is a means of communication. DC 12 volt power lines in the system over the 2-wire control signals with the power to send the cargo configuration, and, in the basement living space, temperature, humidity, dust, CO2 sensors, and through the cooperation of the real-time detection and valves of the appropriate amount of wind, fan was designed to control. By the system's ability to communicate and control the room temperature or the status of amount of wind sent to the central system to transmit and receive signals to the center of the future, the ability to control the company said. In addition, the system HMI (Human Machine Interface) terminal by the direct control and if necessary personal portable devices to communicate with the living conditions of the underground environment in the best state that the purpose is to build.