• The Journal of Korean Institute of Electromagnetic Engineering and Science
• /
• v.29 no.3
• /
• pp.200-213
• /
• 2018

Herein, we survey the current state of the recent legal revision of the Citizens Broadband Radio Service, a type of city spectrum-sharing service used in the United States of America, and the introduction of spectrum sharing in the frequency ranging from 3.8~4.2 GHz, based on the United Kingdom framework for spectrum sharing. Specifically, the subjects of topical interest, including the radio station licensing of the spectrum-sharing service system face-to-face multitier user structure, regional frequency allocation, and applicable service types, are discussed. Furthermore, factors to be considered while selecting candidate channels for joint use are suggested, emphasizing their importance for introducing spectrum sharing in Korea and revitalizing the related industrial sectors. In addition, methods of introducing a radio station license system for spectrum sharing, techniques of introducing incentive auctions, and the types of services where spectrum sharing is applicable are discussed.

• Journal of the Korean Society for Library and Information Science
• /
• v.52 no.3
• /
• pp.121-147
• /
• 2018

Academic libraries in Korea have had more and more troubles in management due to the drastic increase in quantities and budgets for purchasing expensive international academic information resources. In this research, with a focus on the international electronic information resources, an attempt is made to overcome such difficulties in management of academic libraries in the following steps: First, the amount of budgets for purchasing resources and building collections for academic libraries is analyzed; Second, the current state of academic library consortia, both domestic and foreign, is reviewed; Third, the current administrative issues and strategic directions of domestic academic library consortia, including the KESLI Consortium of KISTI, ACE Consortium of KERIS, and Consortium of Korean Council for University Educations, are examined; and Fourth, based on the above collected information, a proposal is made to improve the collection and distribution system for international academic information resources in Korea.

• Journal of the Korea Institute of Information and Communication Engineering
• /
• v.20 no.9
• /
• pp.1785-1790
• /
• 2016

There is exhibit a degree of pain in the occurrence and course of treatment levels or oral, pain rating scale actions, such as illness, for example, the discomfort scale because of the pain "annoying", "unpleasant" "annoyed am", "painful" represents a pain scale of the order of "painful", "hard to bear", "very difficult to bear". Depression is recognized based on the premise of the situation, because it is difficult to recognize themselves. In this paper we define the components of the depression can be seen lifestyle which can lead to depression or through a biological signal. The depression index was derived from the ontology modeling to understand the state of depression. Depression ontology components and depression index will be aware of the situation based information services for depression. Combined with the situational awareness based devices and can be synchronized to verify the results of the depression index. It will be applied to improve lifestyle factors that of depression.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
• /
• v.12 no.2
• /
• pp.184-192
• /
• 2001

In this paper, we analyze the result of the conduced emission and susceptibility tests performed on the KOMPSAT-I ETB Platform. The ETB platform consists of the EM (Engineering Model) boxes developed to perform the electrical functional test. During the conducted emission test, we measured the instant waveform in time domain when each switch was turn on, and spectrum of the noise in the frequency range of 10 Hz up to100 MHz fur the steady state of the ETB. During the conducted susceptibility test, no malfunction and no serious damage of the electronic box were observed when a simulated noise waveform was applied to the DC power bus. The simulated waveform was obtained by adding the 6 dB-system margin to the worst case waveform measured from the conducted emission. This test was performed as co-development of the KOMPSAT-I with TRW in USA.

• Journal of the Korean Ceramic Society
• /
• v.43 no.2 s.285
• /
• pp.121-125
• /
• 2006

[ $LiFePO_4$ ] is one of the promising materials for cathode material of secondary lithium batteries due to its high energy density, low cost, environmental friendliness and safety. $LiFePO_4$ was synthesized by the solid-state reaction method at 500 - 800°C. The crystal structure of $LiFePO_4$ was analyzed by X-ray powder diffraction. The samples synthesized at 600 and $700^{\circ}C$ showed a single phase of a olivine structure. The particle sizes were increased and the specific surface areas were decreased with heating temperatures. The electrochemical performance was investigated by coin cell test. The discharge capacities at 0.1 C-rate were 118 mAh/g and 112 mAh/g at $600^{\circ}C,\;700^{\circ}C$, respectively. In an attempt to improve the electrical conductivity of cathode materials, $LiFePO_4/graphite$ composite was prepared with various graphite contents. The electrical conductivity and discharge capacity were increased with increasing the graphite contents in composite samples. The rate capabilities at high current densities were also improved.

• ETRI Journal
• /
• v.30 no.3
• /
• pp.383-393
• /
• 2008

The etching mechanism of $ZrO_2$ thin films and etch selectivity over some materials in both $BCl_3$/Ar and $BCl_3/CHF_3$/Ar plasmas are investigated using a combination of experimental and modeling methods. To obtain the data on plasma composition and fluxes of active species, global (0-dimensional) plasma models are developed with Langmuir probe diagnostics data. In $BCl_3$/Ar plasma, changes in gas mixing ratio result in non-linear changes of both densities and fluxes for Cl, $BCl_2$, and ${BCl_2}^+$. In this work, it is shown that the non-monotonic behavior of the $ZrO_2$ etch rate as a function of the $BCl_3$/Ar mixing ratio could be related to the ion-assisted etch mechanism and the ion-flux-limited etch regime. The addition of up to 33% $CHF_3$ to the $BCl_3$-rich $BCl_3$Ar plasma does not influence the $ZrO_2$ etch rate, but it non-monotonically changes the etch rates of both Si and $SiO_2$. The last effect can probably be associated with the corresponding behavior of the F atom density.

• Journal of Sensor Science and Technology
• /
• v.18 no.1
• /
• pp.48-53
• /
• 2009

$Eu^{2+}$-doped ${SrAl_2}{O_4}$ and $Eu^{2+}$, $Dy^{3+}$ co-doped ${SrAl_2}{O_4}$ phosphors have been synthesized by conventional solid state method. Photocurrent properties of $Eu^{2+}$ doped ${SrAl_2}{O_4}$ and $Eu^{2+}$, $Dy^{3+}$ co-doped ${SrAl_2}{O_4}$ phosphors, in order to elucidate $Dy^{3+}$ co-doping effect, during and after ceasing ultraviolet-ray (UV) irradiation have been investigated. The photocurrent of $Eu^{2+}$, $Dy^{3+}$ co-doped ${SrAl_2}{O_4}$ phosphors during UV irradiation was 4-times lower than that of $Eu^{2+}$-doped ${SrAl_2}{O_4}$ during UV irradiation, and 7-times higher than that of $Eu^{2+}$-doped ${SrAl_2}{O_4}$ after ceasing UV irradiation. The photocurrent results indicated that holes of charge carriers captured in hole trapping center during the UV irradiation and liberated after-glow process, and made clear that $Dy^{3+}$ of co-dopant acted as a hole trap. The photocurrent of ${SrAl_2}{O_4}$ showed a good proportional relationship to UV intensity in the range of $1{\sim}5mW/cm^2$, and $Eu^{2+}$-doped ${SrAl_2}{O_4}$ was confirmed to be a possible UV sensor.

• Therapeutic Science for Rehabilitation
• /
• v.7 no.2
• /
• pp.9-16
• /
• 2018

Objective : The aim of this research was to provide EEG (electroencephalogram) basic data in clinical areas through identifying measurement tools, measurement methods, and evaluation and analysis method of the EEG which is a neurological change measurement of patients with brain injury. Methods : Previous studies were found in an electronic database (e.g., PubMed, Science Direct). The keyword search terms were 'Electroencephalography', 'stroke', 'intervention OR training'. Results : Utilitizing brain-computer interface, the EEG, which is a tool for measuring the effects of rehabilitation through changes of brain activation state. Also, it could identify functional brain reorganization mechanism. Whenever a research utilized the EEG, which is composed of various channels, different types of electrode, and varied electrode locations. Conclusions : Through this review, we found that Electroencephalography is possible to neurologically verify the effectiveness of intervention and formulate an intervention strategy for efficient occupational therapy.

• Journal of Korean Vacuum Science & Technology
• /
• v.4 no.1
• /
• pp.23-26
• /
• 2000

We have fabricated by metal organic chemical vapor deposition (MOCVD) In$\_$0.13/Ga$\_$0.87/N/GaN multiple quantum well (MQW) with thickness as thin as 10 A and barriers also of th same width on (0001) sapphire substrate. We have investigated this thin MQW by steady-state and time-resolved photoluminescence(PL) in picosecond time scale in a wide temperature range from 10 to 290 K. In the PL at 10 K, we observed a broad peak at 3.134 eV which was attributed to the quantum well emission of InGaN. The full width at half maximum (FWHM) of this peak was 129 meV at 10 K and its broadening at low temperatures was considered to be due to compositional fluctuations and interfacial disorder in the alloy. The narrow width of the quantum well was mainly responsible for the broadening of the emission linewidth. We also observed an intense and sharp peak at 3.471 eV of GaN barrier. From the temperature dependent PL measurements, the activation energy of the InGaN quantum well emision peak was estimated to be 69 meV. The lifetime of the quantum well emission was found to be 720 ps at 10 K, which was explained in terms of the exciton localization arising from potential fluctuations.

• Journal of Institute of Control, Robotics and Systems
• /
• v.6 no.8
• /
• pp.638-651
• /
• 2000

When the bandwidth resources in a packet-switched network are shared among sessions by MAX-MIN flow control each session is required to transmit its data into the network subject to the MAX-MIN fair rate which is solely determined by network loadings. This passive behavior of sessions if fact can cause seri-ous QoS(Quality of Service) degradation particularly for real-time multimedia sessions such as video since the rate allocated by the network can mismatch with what is demanded by each session for its QoS. In order to alleviate this problem we extend the concept of MAX-MIN fair bandwidth allocations as follows: Individual bandwidth demands are guaranteed if the network can accommodate them and only the residual network band-width is shared in the MAX-MIN fair sense. On the other hand if sum of the individual bandwidth demands exceeds the network capacity the shortage of the bandwidth is shared by all the sessions by reducing each bandwidth guarantee by the MAX-MIN fair division of the shortage. we present a novel flow control algorithm to achieve this extended MAX-MIN fairness and show that this algorithm can be implemented by the existing ATM ABR service protocol with minor changes. We not only analyze the steady state asymptotic stability and convergence rate of the algorithm by appealing to control theories but also verify its practical performance through simulations in a variety of network scenarios.