• Journal of Advanced Navigation Technology
• /
• v.17 no.5
• /
• pp.506-515
• /
• 2013

In cognitive radio networks, several research works typically address the framework which consists of a spectrum sensing period and a data transmission period. When the frame period is short, there is the problem that the throughput of secondary users decrease. In this paper, aggregated data slot structure is considered to increase the throughput of secondary users. Chapman-Kolmogorov equation is used for the modeling of the transmission probability of primary users and formulation of an optimization problem to maximize the throughput of secondary users. Solution of the optimization problem results in the optimal spectrum sensing time, the length of data slot and the number of data slots governed by a spectrum sensing.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
• /
• 2009.05a
• /
• pp.281-286
• /
• 2009

The proposed technique uses cyclic frame structure, where three periods such as beacon period (BP), mesh contention access period (MCAP) and slotted period (SP) are in a data frame. This paper studies on a mechanism to allow communication nodes (6lowpan) in a PAN with different logical channel for global healthcare applications monitoring technology. The proposed super framework structure system has installed 6lowpan sensor nodes to communicate with each other. The basic idea is to time share logical channels to perform 6lowpan sensor node. The concept of 6lowpan sensor node and various biomedical sensors fixed on the patient BAN (Body Area Network) for monitoring health condition. In PAN (hospital area), has fixed gateways that received biomedical data from 6lowpan (patient). Each 6lowpan sensor node (patient) has IP-addresses that would be directly connected to the internet. With the help of IP-address service provider can recognize or analyze patient data from all over the globe by the internet service provider, with specific equipments i.e. cell phone, PDA, note book. The NS-2.33 result shows the performance of data transmission delay and data delivery ratio in the case of hop count in a PAN (Personal Area Networks).

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
• /
• v.14 no.6
• /
• pp.1-5
• /
• 2000

Recently alternating-current Plasma Display Panel(AC-PDP) is in the spotlight as a digital television and high definition television. The panel structure widely adapted in commercial AC-PDP is three electrodes surface discharge type. At present time, the luminous efficiency is around 1lm/W, it should be a key factor for the commercialization. For the high luminous efficiency, the development of panel structure is necessary. At a given panel structure, a driving method should be optimized to get a sufficient luminous efficiency. The display image of AC-PDP could be realized by the repeated light emission from the discharge. Because most of discharge power is consumed in the sustaining period, the optimization of sustaining waveform is very important for the high luminous efficiency. ADS (Address and Display period Separated) driving method is commonly used. The average driving frequency of ADS driving method is ranged by several tens kilo of [kHz], however the actual frequency of sustaining period is in range of 100[kHz] to 200[kHz]. Based on this study, when the phosphor emits the visible light, it has a decay time of few milliseconds due to the material transfer to the phosphor to emit the visible light. Consequently the luminous efficiency decreases in proportion to the driving frequency. It is found that the luminous efficiency could be significantly improved by the low frequency sustaining driving method.

• Journal of Korean Library and Information Science Society
• /
• v.39 no.3
• /
• pp.267-297
• /
• 2008

This research purpose to investigate aspect of reading movement and readers' interest in the period of 2000's, This is succession research that is the Japanese Occupation Period, after release, the 1950s, the 1960s, the 1970s, 1980s, 1990s. Through such series, namly, reading phenomenon analyzing comparison, is to find present address of reading popularization movement and reading education. In main discourse, First, investigated reading movement, in the period of 2000's(1. the reading movement of library and public institution, 2. the reading movement of bookstore and medium, and several organization's, 3. student reading movement and school reading education). Second, readers' interest observed in the period of 2000's.(1. ordinary readers' interest, 2. student readers' interest). If we correct judgment about reading phenomenon from now. It will be foundation that unfold reading education more effectively.

• The Journal of the Korea Contents Association
• /
• v.11 no.10
• /
• pp.267-273
• /
• 2011

The purpose of this paper is to suggest the types of recovery activities and the major contents of preimpact recovery plan through theoretical review. Disaster recovery is to provide immediate support during the early recovery period necessary to return vital life support systems to minimum operation levels, and continuing to provide support until the community returns to normal. Disaster researchers distinguished 4 types in recovering from disaster as follows; an emergency period, a restoration period, a reconstruction period, and a developmental reconstruction period. And recovery measures are both short-term and long-term. Short-term measures are relief and rehabilitation and long-term measures include reconstruction. Finally, to design a preimpact recovery plan, we should define a disaster recovery organization that includes major stakeholders, identify the location of temporary housing, determine how to perform essential tasks, address the licensing and monitoring of contractors and retail price controls to ensure victims are not exploited, determine how recovery tasks will be carried out at historical sites, and recognize the recovery period as a unique time to enact policies for hazard mitigation and incorporate this objecive into the recovery planning process.

• The Transactions of the Korean Institute of Power Electronics
• /
• v.10 no.6
• /
• pp.578-586
• /
• 2005

Recently, due to the launch of digital broadcasting service, the demand of Flat Panel Display (FPD) is sharply rising. Among them, the PDP is expected to be one of the most promising digital displays of next generation because of its large screen size, high resolution, thinness and board field of view. Meanwhile, the PDP uses ADS (Address Display-period Separation) scheme which divide one subfield into address and sustaining period to express the grey scale of images. Since the output of sustaining power module Is mostly used for sustaining period, the load of the sustaining power module can be considered as a pulsating load. Due to this particular load condition, if the wide ZVS range of the power switches is not guaranteed, the hard switching causes large amount of switching loss and serious thermal problem in power module. In this paper, a high efficiency power conversion circuit for 60' PDP sustaining power module which achieves wide ZVS range with the help of additional ZVS tank is proposed. According to the various gating methods, the different operations of the proposed converter are presented. And, to confirm the properties of the proposed converter, an experimental prototype of 900W power converter is constructed md tested. As a result, more than $92\%$ of high efficiency is obtained at $10\%$ load condition, and the ZVS operation is achieved from full load to $10\%$ load condition.

• Journal of Animal Science and Technology
• /
• v.59 no.4
• /
• pp.7.1-7.13
• /
• 2017

Background: Selenium is one of the trace minerals whose deficiency is known to lead to complications of female reproduction. The identified gaps in researches regarding selenium and pregnancy include optimizing the dosage of selenium supplementation, timing of supplementation, finding the best form and type of selenium, and selenium administration combined with other antioxidants. Hence, this study was conceptualized to address one of the identified gaps, that is, to find out the best timing of selenium administration around the time of pregnancy. Specifically, this study aimed to assess the effects of maternal Selenium-supplementation, administered at various stages of periconception period, on murine blastocyst morphology, percent occurrence of good quality blastocysts, and implantation status. Methods: ICR female mice were randomly assigned into the unsupplemented group (Group I) receiving basal diet without selenium, and treatment groups given with $3.0{\mu}g$ selenium-supplement per day during pregestation only (Group II), pregestation-throughout-gestation (Group III) and gestation only (Group IV). Both blastocyst morphology and implantation status were assessed. Results: The morphometric measurements of blastocysts appeared to be unaffected by selenium-supplementation at different stages of periconception. Selenium-supplementation at pregestation only (Group II) and gestation only (Group IV) produced higher percent occurrence of good quality blastocysts and lower percent pre-implantation loss than Group III. Among all the treatment groups, Group III (Selenium-supplementation during pregestation-to-gestation) yielded the lowest quality blastocysts and highest percent pre-implantation loss. Conclusion: Maternal selenium-supplementation during pregestation and gestation stages of the periconception period yielded a high percent occurrence of good quality blastocysts and pre-implantation success.

• 한국정보디스플레이학회:학술대회논문집
• /
• 2003.07a
• /
• pp.722-725
• /
• 2003

In AC plasma display, it is very important to quantify the wall voltage induced by the wall charge accumulated on the dielectric surface. If we know the quantities of the wall voltage in each period of every sequence; reset period, address period and sustain period, then it helps us to design the optimal driving waveform for high efficiency plasma display. We develop a new method to measure the wall voltage with VDS (Versatile Driving Simulator) system. From this method the wall voltage induced by a wall charge profiles just after the reset discharge of every cells in plasma display panel can be investigated and analyzed successfully. It is noted that the wall voltage profiles are influenced by the space charge and then they are stabilized as time goes by. It is also noted that both the remaining wall charge at the previous sequence and space charges contribute to wall voltage quantities just after the reset discharge. It is noted that the wall charges contribute dominantly after a few hundreds microseconds, while the space charges have been decayed within 100 ${\mu}s$ just after the reset discharge.

• Journal of Korean Library and Information Science Society
• /
• v.39 no.1
• /
• pp.377-407
• /
• 2008

This research allows purpose to investigate aspect of reading movement and reading education in the early period of the 1990's. This is succession research that is the Japanese Occupation Period, after release, the 1950's, the 1960's, the 1970's, the 1980's reading popularization movement research as current trend of opinion to examine modern reading popularization movement. Such series research that reading phenomenon analyzing comparison, is to find present address of reading movement and reading education. accordingly all sorts correct judgment about reading phenomenon, hereafter that will be foundation that unfold reading education more effectively. In main discourse first, investigated, reading movement, and second, observed classifying distinguish reading of student from reading of ordinary people by readers' interest etc.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
• /
• v.20 no.7
• /
• pp.14-20
• /
• 2006

The discharge characteristics for the reset period of sustain pulses of display discharge in address overlapped display driving methode is studied. It has been understood that the display discharge is strongly influenced of not only the wall charge but also the space charge from the experiment result. The first display discharge which comes out exactly after the rest periods strongly depends on the width of the reset period and as for the second display discharge, the dependancy of it is very low. Even if the first display discharge is a little insufficient if the wall charge is accumulated enough, the second display discharge can be stably induced. However, considering the influence of the space charge, it is preferable within the width of $30[{\mu}s}]$ of the reset period. When the rest period is up to $30[{\mu}s}]$, the uniform voltage operation margin of the display discharge of about 12[V] was obtained.