• Journal of Broadcast Engineering
• /
• v.2 no.2
• /
• pp.86-93
• /
• 1997

Fast growth of multimedia applications requires new functions for video data processing. such as obj;cted-based video representation and manipulation. which are not supported by 11PEG-l and 11PEG-2. To support these requirements. 11PEG-4 video coding allows users to manipulate every video object easily by decomposing a scene into several video objects and coding each of them independently. However. the large amount of computations and flexible structure of 11PEG-4 video CODEC make it difficult to be implemented by either the general purpose DSP or a dedicated VLSI. In this paper, we propose a hardware architecture using a hybrid of a high performance programmable DSP and an application specific IC to implement a flexible 11PEG-4 video codec requiring the large amount of computations. The application specific IC has the functions of motion estimation and compensation.

• Proceedings of the KIEE Conference
• /
• 2004.07c
• /
• pp.2052-2054
• /
• 2004

The TX/RX broadband L-type circular polarization antenna using LTCC at K/Ka band has been presented. This antenna has been analyzed in compensation for LTCC with relative permittivity 5.2 and could have been integrated with RF component. As the measured 10dB impedance circular polarization bandwidth of the proposed antenna is 7%(20.8GHz${\sim}$22.2GHz) at the K band and 2.3%(30.9GHz to 31.6GHz) at the Ka band. Also the gain of the antenna is -0.7${\sim}$3.05dBi at the K band and -2.8${\sim}$1dBi at the Ka band. The purpose of the research is to design an efficient antenna structure for satellite communication at K/Ka band. the antenna should be used for both TX and RX frequency bands. The antenna will be mounted on LTCC(Low Temperature Co-fired Ceramic) so that it can be integrated with other RF circuits. This research is important because of the following reasons. 1) The frequency ranges of satellite communication tends to move up to higher frequency such as Ka band or milimeter wave band. 2) Design of antenna for smaller size, lighter weight and less loss is preferred by most RF engineers. 3) Antennas on LTCC enables to integrate the antenna with other RF circuits, and thus, one can reduce the size and loss of the RF system.

• Journal of Ocean Engineering and Technology
• /
• v.33 no.6
• /
• pp.648-656
• /
• 2019

The ecological changes in the ocean due to the drastic global warming require that action be taken to sustain the productivity of fisheries. Proper ocean facilities could help prevent the loss of the expenditures made on marine aquaculture and reduce the related compensation for various ocean conditions. The aim of this study was to develop a floating ocean wave-breaker using an eco-friendly concrete and conducting a site survey, a structural analysis, and a test of towing the tank. As a result, the wave at the fish farm would be reduced. The results of the holding power of anchors and the capability of moving the floating structures were considered in the design of the wave-breaker. The analyses of the material properties of concrete and the steel structures, as well as the CAPEX and OPEX analyses of the manufacturing and operation processes confirmed the superiority of the floating concrete wave-breaker. In particular, this study demonstrated that the concrete floating breakwater can protect the fish farm against typhoons and reverse-waves, thereby reducing losses of the fish.

• Korean Journal of Occupational Health Nursing
• /
• v.27 no.3
• /
• pp.180-189
• /
• 2018

Purpose: The aim of this study was to investigate the influence of nurses' awareness of healthcare accreditation on their job stress and turnover intention. Methods: Across-sectional correlation study design was used. Participants consisted of 143 nurses from two tertiary hospitals in Seoul and Gyunggido, South Korea. Data were collected in October 2016 using self-report questionnaires and analyzed using descriptive statistics, t-test, an ANOVA, Pearson's correlation coefficient, and multiple regression in SPSS/WIN 21.0. Results: Awareness of health care accreditation correlated negatively with job stress (r=-.63, p<.001) and turn over intention (r=-.50, p<.001). Awareness of health care accreditation was the factor that most influenced job stress, explaining 38% of the variance (F=23.10, p<.001). Awareness of health care accreditation and duty pattern were the factors that most influenced intention to leave, explaining 32% of the variance (F=10.35, p<.001). Conclusion: These findings suggest raising nurses' awareness of certification systems to reduce their job stress and turnover intentions. It will be necessary to provide support for the aggressive work nurses do and improve their work structure, highlighting the need for both manpower and institutional support. Accordingly, providing regular education programs and appropriate compensation schemes, by raising nurses' awareness of medical institutions' certification systems, is necessary.

• Journal of Ecology and Environment
• /
• v.36 no.4
• /
• pp.223-233
• /
• 2013

Acid deposition is one of the most serious environmental problems in ecosystems. The present study surveyed the effects of simulated acid rain on leaf litter mass loss and microbial community in the decomposing leaf litter of Sorbus anifolia in a microcosm at $23^{\circ}C$ and 40% humidity. Microbial biomass was measured by substrate-induced respiration (SIR) and phospholipid fatty acids (PLFAs), and the microbial community structures were determined by composition of PLFAs at each interval of decomposition in litter sample and at each pH treatment. The microbial biomass showed peaks at mid-stage of decomposition, decreasing at the late stage. The leaf litter mass loss of S. anifolia decreased with decreasing pH during early and mid-decomposition stages; however the mass loss becomes similar between pH treatments at late-decomposition stage. The acidification remarkably lowers the microbial biomass of bacteria and fungi; however, microbial diversity was unchanged between pH treatments at each stage of litter decomposition. With changes of decomposition stage and pH treatment there were considerable differences in replacement and compensation of microbial species. Fungi/bacteria ratio was considerably changed by pH treatment. The PLFA profile showed significantly larger fungi/bacteria ratio at pH 5 than pH 3 at the early stage of decomposition, and the difference becomes smaller at the later decomposition stage. At low pH, pH 3 and pH 4, the fungi/bacteria ratios were stable according to the litter decomposition stages. Simulated acid rain caused decreases of 10Me17:0, 16:1${\omega}$7c, 18:1${\omega}$7, 15:0, but increase of 24:0. In addition, litter mass loss showed significant positive correlation with microbial biomass measured by SIR and PLFA on the decomposing leaf litter.

• Journal of the Korean Ceramic Society
• /
• v.48 no.4
• /
• pp.323-327
• /
• 2011

The effects of $Dy_2O_3$ and $Er_2O_3$ co-doping on electrical properties and temperature stability of barium titanate ($BaTiO_3$) ceramics were investigated in terms of microstructure and structural analysis. The dielectric constant and the insulation resistance (IR) of 0.7 mol% $Dy_2O_3$ and 0.3 mol% $Er_2O_3$ co-doped dielectrics had about 60% and 20% higher than the values of undoped one, respectively, and the temperature coefficient of capacitance (TCC) met the X7R specification. The addition of $Dy_2O_3$ contributed to electrical properties caused by increase of tetragonality; however, preferential diffusion of $Dy^{3+}$ ions toward A site in $BaTiO_3$ grain exhibited an adverse effect on temperature stability by grain growth. On the other hand, The $Er_2O_3$ addition in $BaTiO_3$ could affect the TCC behavior and the IR with suppression of grain growth caused by reinforcement of grain boundary and electrical compensation. Therefore, the enhanced electrical properties and temperature stability through the co-doping could be deduced from the increase of tetragonality and the suppression of grain growth.

• The Journal of Korean Institute of Communications and Information Sciences
• /
• v.22 no.6
• /
• pp.1231-1243
• /
• 1997

Digital satellite communication channels have nonlinearities with memory due to saturation characteristics of traveling wave tube amplifier in the satellite and transmitter/receiver linear filters. In this paper, we propose a network structure and a learning algorithm for complex pi-sigma network (CPSK) and exploit CPSN in the problem of equalization of nonlinear satellite channels. The proposed CPSN is a complex-valued extension of real-valued pi-sigma network that is a higher-order feedforward network with fast learning while greatly reducing network complexity by utilizing efficient form of polynomials for many input variables. The performance of the proposed CPSN is demonstrated by computer simulations on the equalization of complex-valued QPSK input symbols distorted by a nonlinear channel modeled as a Volterra series and additive noise. The results indicate that the CPSN shows good equalization performance, fast convergence, and less computations as compared to conventional higher-order models such as Volterra filters.

• Journal of Sensor Science and Technology
• /
• v.26 no.3
• /
• pp.179-185
• /
• 2017

This article describes the characteristics of nondispersive infrared carbon dioxide gas sensor according to the temperatures and humidifies. In this researches, a thermopile sensor that included application-specific integrated circuit (ASIC) was used and the White-cell structure was implemented as an optical waveguide. The developed sensor modules were installed in gas chamber and then the temperature of gas chamber has been increased from 283 K to 313 K with 10K temperature step. In order to analyze the effects of humidity levels, the relative humidity levels were changed from 30 to 80%R.H. with small humidifier. Then, the characteristics of sensor modules were acquired with the increment of carbon dioxide concentrations from 0 to 2,000 ppm. When the initial voltages of sensors were compared before and after humidifying the chamber at constant temperature, the decrements of the output voltages of sensors are like these: 9mV (reference infrared sensor), 41 mV (carbon dioxide sensor), 2 mV (temperature sensor). With the increment of ambient temperature, the averaged output voltage of carbon dioxide sensor was increased 19 mV, however, when the humidity level was increased, it was decreased 14mV. Based upon the experimental results, the humidity effect could be alleviated by the increment of temperature, so the effects of humidity and temperature could be only compensated by the ambient temperature itself. The estimated carbon dioxide concentrations showed 10% large errors below 200 ppm, however, the errors of the estimations of carbon dioxide concentrations were less than ${\pm}5%$ from 400 to 2,000 ppm.

• Journal of the Korean Vacuum Society
• /
• v.18 no.6
• /
• pp.435-439
• /
• 2009

The reason of lowering the dielectric constant of SiOC film was studied using parameters obtained from C-V measurement and refractive index. SiOC film was formed by the force of ionic bonding during the recombination of dissociated gases. Generally, the dielectric constant was obtained from the square of the refractive index or C-V measurement using the metal/insulator/Si structure. The dielectric constant consists of the ionic and electronic elements. It was researched about the dielectric constant of SiOC film using the average of the ionic and electronic elements. The dielectric constant decreased after annealing process. As deposited films trended toward the dielectric constant consisted of most ionic elements, on the other hand, annealed films mostly consisted of electronic elements. Because the effect of ionic elements reduced after annealing. Consequently, it was found that the electronic effect of SiOC film increased and the ionic effect of SiOC film decreased by the after-annealing.

• The Journal of the Korea Contents Association
• /
• v.15 no.8
• /
• pp.408-415
• /
• 2015

This study investigated the job-satisfaction of the Radiographer's job-characteristics and job-stress. A total of 213 Radiographer were surveyed using a self-administered questionnaire. The 105 questionnaires consist of general characteristics, job characteristics, occupational stress, and job satisfaction. The job satisfaction was categorized into 3 sub-scales; psychological variables, environmental variables, and structural variables. The occupational stress was categorized into 8 sub-scales; physical environment, job demand, insufficient job control, interpersonal conflict, job insecurity, organizational system, lack of reward, and occupational climate. 30 years old than 30 years later, people are highly rewarding than a low person, this person is lower than people with high sense of duty, place the larger the size of Seoul, hospital than fat, than people who do not have turnover intention this, job insecurity, organizational structure, inadequate compensation, workplace culture, physical environment, people with low job satisfaction is higher than men were. As such there is a need to identify the cause because otherwise indicated differences in job satisfaction.