• Journal of the Korean Institute of Electrical and Electronic Material Engineers
• /
• v.11 no.12
• /
• pp.1122-1127
• /
• 1998

Group II-AF_2$films such as $CaF_2$, $SrF_2$, and $BaF_2$ have been commonly used many practical applications such as silicon on insulatro(SOI), three-dimensional integrated circuits, buffer layers, and gate dielectrics in filed effect transistor. This paper presents electrical and structural properties of fluoride films as a gate dielectric layer. Conventional gate dielectric materials of TFTs like oxide group exhibited problems on high interface trap charge density($D_it$), and interface state incorporation with O-H bond created by mobile hydrogen and oxygen atoms. To overcome such problems in conventional gate insulators, we have investigated $CaF_2$ films on Si substrates. Fluoride films were deposited using a high vacuum evaporation method on the Si and glass substrate. $CaF_2$ films were preferentially grown in (200) plane direction at room temperature. We were able to achieve a minimum lattice mismatch of 0.74% between Si and $CaF_2$ films. Average roughness of $CaF_2$ films was decreased from 54.1 ${\AA}$ to 8.40 ${\AA}$ as temperature increased form RT and $300^{\circ}C$. Well fabricated MIM device showed breakdown electric field of 1.27 MV/cm and low leakage current of $10^{-10}$ A/$cm^2$. Interface trap charge density between $CaF_2$ film and Si substrate was as low as $1.8{\times}10^{11}cm^{-2}eV^{-1}$.

• Journal of the Korean Magnetics Society
• /
• v.14 no.4
• /
• pp.131-137
• /
• 2004

For the aim of thin electromagnetic wave absorbers used in mobile telecommunication frequency band (0.8-2.0㎓), we investigate high-frequency magnetic, dielectric and microwave absorbing properties of iron particles dispersed in rubber matrix in this study. The major experimental variables are particle shape (sphere and flake) and initial particle size (in the range 5-70 $\mu\textrm{m}$) of iron powders. High value of magnetic permeability and dielectric permittivity can be obtained in the composites containing thin plate-shape (flake) iron particles (of which thickness is less than skin depth in ㎓frequency), which can be produced by mechanical forging of spherical iron powders using an attrition mill. This result is attributed to the reduction of eddy current loss (increase of permeability) and the increase of space charge polarization (increase of permeability). The optimum initial particle size is found to be about 10 $\mu\textrm{m}$ for the attainment of the material parameters (particularly, real part of complex permeability) satisfying the wave impedance matching. With the iron powders controlled in size and shape as absorbent fillers in rubber matrix, the thickness can be reduced to about 0.7mm with respect to -5㏈ reflection loss (70% power absorption) in mobile telecommunication frequency band.

• Journal of Internet Computing and Services
• /
• v.19 no.6
• /
• pp.31-40
• /
• 2018

With the development of IT technology recently, medical information systems are being constructed in an integrated u-health environment through cloud services, IoT technologies, and mobile applications. These kinds of medical information systems should provide the medical staff with authorities to access patients' medical information for emergency status treatments or therapeutic purposes. Therefore, in the medical information systems, the reliable and prompt authentication processes are necessary to access the biometric information and the medical information of the patients in charge of the medical staff. However, medical information systems are accessing with simple and static user authentication mechanism using only medical ID / PWD in the present system environment. For this reason, in this paper, we suggest a dynamic situation authentication mechanism that provides transparency of medical information access including various authentication factors considering patient's emergency status condition and dynamic situation authentication system supporting it. Our dynamic Situation Authentication is a combination of user authentication and mobile device authentication, which includes various authentication factor attributes such as emergency status, role of medical staff, their working hours, and their working positions and so forth. We designed and implemented a dynamic situation authentication system including emergency status decision, dynamic situation authentication, and authentication support DB construction. Finally, in order to verify the serviceability of the suggested dynamic situation authentication system, the medical staffs download the mobile application from the medical information server to the medical staff's own mobile device together with the dynamic situation authentication process and the permission to access medical information to the patient and showed access to medical information.

• Proceedings of the Korean Society of Broadcast Engineers Conference
• /
• 2014.06a
• /
• pp.157-159
• /
• 2014

In this paper, we introduce SlimSRP, an ultra-low-power digital signal processor (DSP) solution for mobile audio and voice applications. So far, application processors (APs) have taken charge of all the tasks in mobile devices. However, they have suffered from short battery life problems to deal with complex usage scenarios, such as always-on voice trigger with continuous audio playback. From extensive analysis of audio and voice application characteristics, SlimSRP is designed to relive the performance and power burden of APs. It employs three-issue VLIW architecture, and the major low-power and high-performance techniques include: (1) an optimized register-file architecture friendly for constants generation, (2) a powerful instruction set to reduce the number of register file accesses and (3) a unique instruction compression scheme that contributes to saved memory size and reduced cache miss. An implementation of SlimSRP runs at up to 200MHz and the logic occupies 95K NAND2 gates in Samsung 28LPP process. The experimental results demonstrate that a MP3 decoder application with a 128kbps 44.1kHz input can run at 5.1MHz and the logic consumes only 22uW/MHz.

• Membrane and Water Treatment
• /
• v.6 no.2
• /
• pp.127-139
• /
• 2015

Rejection of ionic solutes by reverse osmosis (RO) and nanofiltration (NF) membranes is controlled mainly by electrochemical interaction as well as pore size, but it is very difficult to directly evaluate such electrochemical interaction. In this work, we used an inverse HPLC method to investigate the interaction between ionic solutes and poly (m- phenylenediaminetrimesoyl) (PPT), a polymer similar to the skin layer of polyamide RO and NF membranes. Silica gel particles coated with PPT were used as the stationary phase, and aqueous solutions of the ionic solutes were used as the mobile phase. Chromatographs obtained for the ionic solutes showed features typical of exclusion chromatographs: the ionic solutes were eluted faster than water (mobile phase), and the exclusion intensity of the ionic solute decreased with increasing solute concentration, asymptotically approaching a minimum value. The charge density of PPT was estimated to be ca. 0.007 mol/L. On the basis of minimum exclusion intensity, the exclusion distances between a salt and neutralized PPT was examined, and the following average values were obtained: 0.49 nm for 1:1 salts, 0.57 nm for 2:1 salts, 0.60 nm for 1:2 salts, and 0.66 nm for 2:2 salts. However, $NaAsO_2$ and $H_3BO_3$, which are dissolved at neutral pH in their undissociated forms, were not excluded.

• Journal of KIISE:Information Networking
• /
• v.27 no.1
• /
• pp.30-38
• /
• 2000

In distributed HLR environment, the pointer forwarding with distributed HLR(Pointer Forwarding Scheme) has been proposed for eliminating the cost of updating multiple HLRs. In Pointer Forwarding Scheme, the find cost can be changed according to from which HLR a call originates. If a user changes PCS registration areas frequently, but receives calls relatively infrequently, and call for such a user originates from any other HLRs than the recently updated HLR, many VLRs should be traversed in order to find that user. In this paper, location tracking with jumping pointer in distributed HLR(Jumping Pointer Scheme) is proposed. The jumping pointer can be connected between the recently updated VLR and the VLR in which the mobile host currently resides. In case of call delivery, the mobile host can be found sooner by using the jumping pointer. In terms of 'find' cost, Jumping Pointer scheme improves about 17% over Forwarding Pointer scheme. Otherwise, Jumping Pointer scheme takes additional update charge in order to manage the jumping pointer. However the total costs of 'find' cost and 'update' cost for Jumping Pointer scheme are cheaper than them for Forwarding Pointer scheme when call-to-mobility ratio is smaller.

• The Korean Journal of Applied Statistics
• /
• v.21 no.5
• /
• pp.791-799
• /
• 2008

Ansim Flat DATA Plan is a DATA additional service product related to DATA call in a mobile telephone company A. Up to now, the company A is selling it by outbound TM after targeting customers which used data within specific price band. In this paper, we propose a targeting method applying score model combining response rate and retention rate by data mining. The suggested target model is to find customers more likely not only to respond to outbound TM but also to retain Ansim Flat DATA Plan. The proposed targeting method is expected to improve both from 23.7% to 38.8% in the response rate and from 53.2% to 61.4% in the retention rate.

• Proceedings of the Korean Nuclear Society Conference
• /
• 1996.05c
• /
• pp.231-237
• /
• 1996

Defect equilibrium equations were modelled, and the relations of P $o_2$, venus x were derived using the mass action law. The dominant defect species active in a specified region were determined by fitting the curve of experimental data to the calculated curve of log P $o_2$, versus log x for each theoretical model. The calculated curve for (2:1:2) and (Er')$^{x}$ in the hyperstoichiometric $U_{1-y}$E $r_{y}$ $O_{2＋x}$ and that for (2Er'quot;)$^{x}$ $_{dec}$ in the hypostoichiometric $U_{1-y}$E $r_{y}$ $O_{2－x}$ are in good agreement with the present experimental results. The sintering behavior of Er-doped U $O_2$ is observed with erbium content in oxidizing and reducing atmospheres. For sintering in oxidizing atmosphere, sintered density decreases as increasing y in $U_{1-y}$E $r_{y}$ $O_{2＋x}$. However, in hydrogen atmosphere, sintered density decreases as increasing y at lower erbium content but the density increases again above y=0.10. In oxidizing sintering conditions, the formation of (Er'U')$^{x}$ clusters hinders the diffusion of cations, and hence the sinterability of Er-doped U $O_2$ decreases. In reducing atmosphere of Er-doped U $O_2$ for higher Er concent, the oxygen vacancies make (Er')$^{x}$ cluster decompose by charge compensation and the concentration of mobile cations increases, thereby improving the sinterability.ntration of mobile cations increases, thereby improving the sinterability.ability.

• Journal of the Korean Society of Radiology
• /
• v.10 no.1
• /
• pp.59-64
• /
• 2016

The purpose of this study intend to develop the automatic voice system for language communicating over foreign patients in testing of magnetic resonance imaging. Used sentences for the automatic voice system was selected with twelve sentences and five foreign languages in hospital in use. These translated texts were provided free of charge from Oddcast's website, which is recorded each language-specific voice as Wav files, The recorded audio file were produced by the two types of a power-point show of MS-office 2013(extension; ppsx) form and Web-enabled system using the PHP program to be applied in the mobile phone environment. It is considered to relieve the stress about an language barrier to medical technician and the voice system designed with the variable language will be enhanced the diagnostic information on foreign patients. Because automatic voice system designed for this study can enhance the understanding of test in between korean medical technician and foreign patients, It will be expected to utilize more usefully in clinical practice.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
• /
• 2013.05a
• /
• pp.227-230
• /
• 2013

Financial transactions using a mobile terminal and the Internet is activated, it is a stock exchange enabled using mobile devices and the Internet. Koscom in charge of IT operations of securities transaction-related in (securities ISAC), to analyze the vulnerability of information security related to securities transactions, which corresponds to running the integrated security control system. Online stock trading is a subject to the Personal Information Protection Act, electronic systems of related, has been designated as the main information and communication infrastructure to, damage financial carelessness of the user, such as by hacking is expected to are. As a result, research on the key vulnerabilities of information security fields related to securities business cancer decoding of the Securities and Exchange packet, through the analysis of security events and integrated security control is needed.