• The Journal of Korean Institute of Communications and Information Sciences
• /
• v.27 no.4B
• /
• pp.379-387
• /
• 2002

In this paper, we present a procedure to obtain the transient scattering response from three-dimensional arbitrarily shaped and closed conducting bodies using time-domain magnetic field integral equation (TD-MFIE) with triangular patch functions. This approach results in accurate and comparably stable transient responses from conducting scatterers. Detailed mathematical steps are included, and several numerical results are presented and compared with results from a time-domain electric field integral equation (TD-EFIE) and the inverse courier transform solution of the frequency domain results.

• KSII Transactions on Internet and Information Systems (TIIS)
• /
• v.18 no.1
• /
• pp.233-262
• /
• 2024

Due to the rapid evolution of vehicular ad hoc networks (VANETs), effective communication and security are now essential components in providing secure and reliable vehicle-to-vehicle (V2V) and vehicle-to-infrastructure (V2I) communication. However, due to their dynamic nature and potential threats, VANETs need to have strong security mechanisms. This paper presents a novel approach to improve VANET security by combining the Vehicular Delay-Tolerant Network (VDTN) protocol with the Deep Reinforcement Learning (DRL) technique known as the Twin Delayed Deep Deterministic Policy Gradient (TD3) algorithm. A store-carry-forward method is used by the VDTN protocol to resolve the problems caused by inconsistent connectivity and disturbances in VANETs. The TD3 algorithm is employed for capturing and detecting Worm Hole Attack (WHA) behaviors in VANETs, thereby enhancing security measures. By combining these components, it is possible to create trustworthy and effective communication channels as well as successfully detect and stop rushing attacks inside the VANET. Extensive evaluations and simulations demonstrate the effectiveness of the proposed approach, enhancing both security and communication efficiency.

• Journal of the Korean Society of Food Culture
• /
• v.19 no.4
• /
• pp.419-428
• /
• 2004

The Purpose of this study was to investigate the effect of dietary sea tangle in diabetic rats treated with streptozotocin(STZ). Four groups of rats (Sprague-Dawley male rats,180-200g) were normal rats fed control diet(C), diabetic rats fed control diet(CD), normal rats fed sea tangl diet(T), and diabetic ,rats fed sea tangle diet(TD), diabetes was induced by single injection of streptozotocin(60mg/kg B.W.). High density lipoprotein(HDL) of T and TD group were higher than other groups(C and T groups). And the weekly change of blood sugar was decreased in the 3th and 4th weeks. But serum triglyceride (TG) of diabetic rats fed sea tangle diet(TD) was lower than diabetic rats fed control dlet(CD). Activity of hepatic microsomal Glucose 6-phosphatase(G6Pase) was significantly increased CD and TD groups higher than C and T groups. Hepateic glutathione S-transferase(GST of T, CD and TD groups were significantly lower than C group(p<0.05), glutathione peroxidase (GPX) of T and TD groups were significantly higher than C and CD groups(p<0.05).

• Asian Pacific Journal of Cancer Prevention
• /
• v.15 no.10
• /
• pp.4339-4347
• /
• 2014

Purpose: This study aimed at exploring treatment delay (TD) among cancer patients in China with an attempt to develop a practical methodology facilitating frontline Chinese clinicians in promoting earlier cancer diagnosis and treatment. Materials and Methods: The study comprised framework development, qualitative interviews and paired factor rating. Framework development utilized systematic literature review, soft systems thinking and consensus groups. Qualitative interviews employed a checklist of open questions soliciting information about all the domains included the framework from cancer patients drawn via stratified randomized sampling of inpatients at 10 hospitals in Hefei, China. Paired factor rating used a self-developed computer aid and the interviewed patients as referring cases to weigh the relative importance of the factors listed in the framework in terms of their contributions to specific components of total delay (TD). Results: a) A conceptual framework was proposed consisting of a 6-step path to TD and 36 category determinants. b) A total of 227 patients were interviewed; their TD was 267.3 mean or 108 median days ranging from 0 to 2475 days; average appraisal, illness, behavioral, preparation and treatment delay accounted for 52.1%, 9.4%, 0.30%, 8.8% and 29.4% of the TD respectively. Individual side factors were rated substantially more important than environmental side factors (60% vs. 40%); most influential TD factors included cancer symptoms, overall health, family relations and knowledge about cancer and health. Conclusions: The framework proposed together with the interviewing and rating approaches used provide a potential new methodology for understanding cancer patients' TD and promoting earlier cancer treatment.

• Korean Journal of Materials Research
• /
• v.25 no.1
• /
• pp.1-8
• /
• 2015

This study suggested comprehensive structural characterization methods for the commercial blue light emitting diodes(LEDs). By using the Z-contrast intensity profile of Cs-corrected high-angle annular dark field scanning transmission electron microscope(HAADF-STEM) images from a commercial lateral GaN-based blue light emitting diode, we obtained important structural information on the epilayer structure of the LED, which would have been difficult to obtain by conventional analysis. This method was simple but very powerful to obtain structural and chemical information on epi-structures in a nanometer-scale resolution. One of the examples was that we could determine whether the barrier in the multi-quantum well(MQW) was GaN or InGaN. Plan-view TEM observations were performed from the commercial blue LED to characterize the threading dislocations(TDs) and the related V-pit defects. Each TD observed in the region with the total LED epilayer structure including the MQW showed V-pit defects for almost of TDs independent of the TD types: edge-, screw-, mixed TDs. The total TD density from the region with the total LED epilayer structure including the MQW was about $3.6{\times}10^8cm^{-2}$ with a relative ratio of Edge- : Screw- :Mixed-TD portion as 80%: 7%: 13%. However, in the mesa-etched region without the MQW total TD density was about $2.5{\times}10^8cm^{-2}$ with a relative ratio of Edge- : Screw- :Mixed-TD portion of 86%: 5%: 9 %. The higher TD density in the total LED epilayer structure implied new generation of TDs mostly from the MQW region.

• Proceedings of the IEEK Conference
• /
• 2008.06a
• /
• pp.267-268
• /
• 2008

TD-SCDMA is considered as an innovative Chinese 3G technology adopted by the ITU for the IMT-2000 family. TD-SCDMA combines TDMA and CDMA components to provide more efficient use of radio resources. According to the traffic volume and activity level, the operation mode of a mobile terminal can change from one state to other states. This paper focuses on the problem of recovery delay from inactive states, and proposes a resource management algorithm, which holds some resources for rapid recovery of service after the service determines to release the dedicated resources.

• The Journal of Korean Institute of Communications and Information Sciences
• /
• v.26 no.10A
• /
• pp.1645-1652
• /
• 2001

제3세대 이동 통신 시스템에서 상향 링크와 하향 링크 사이에 불균형적인 타임 슬롯 할당이 가능한 TD/CDMA TDD 시스템은 비대칭적인 트래픽을 효과적으로 분배하는데 적합하다. 게다가 TD/CDMA TDD 시스템은 슬롯이 시간 영역과 코드 영역에서 정의되기 때문에 유효 자원의 statistical multiplexing이 매우 효과적이다. 그러나 상향 링크와 하향 링크사이의 트래픽의 비대칭성을 반영하기 위해서 타임 슬롯을 최적으로 할당시킬 수 있는 동적 경계선이 요구된다. 본 논문에서 슬롯의 하향 링크부분이 이동국의 접근 시도의 정도에 따라 최대화되는 새로운 최적의 TDD 경계선 제어 움직임 알고리즘을 제안하였다. 제안된 알고리즘에서 이동국의 평균 접근 시도가 미리 정의된 상한 임계치를 초과할 경우, TDD 경계선은 평균 접근 시도가 다른 하한 임계치 아래로 내려갈 때까지 프레임의 중앙에 위치한다. 본 논문에서 모의실험 결과를 통하여 제안된 알고리즘이 기존의 TDD 경계선 알고리즘보다 데이터 트래픽의 평균 접근 지연과 음성 트래픽의 블록킹 확률 측면에서 훨씬 더 좋은 성능을 나타냄을 입증하였다.

• Bulletin of the Korean Chemical Society
• /
• v.34 no.8
• /
• pp.2276-2280
• /
• 2013

The accurate prediction of vertical excitation energies is very important for the development of new materials in the dye and pigment industry. A time-dependent density functional theory (TD-DFT) approach coupled with 22 different exchange-correlation functionals was used for the prediction of vertical excitation energies in the halogenated copper phthalocyanine molecules in order to find the most appropriate functional and to determine the accuracy of the prediction of the absorption wavelength and observed spectral shifts. Among the tested functional, B3LYP functional provides much more accurate vertical excitation energies and UV-vis spectra. Our results clearly provide a benchmark calibration of the TD-DFT method for phthalocyanine based dyes and pigments used in industry.

• Journal of Society of Preventive Korean Medicine
• /
• v.18 no.1
• /
• pp.11-21
• /
• 2014

Objective : This study set out to combine the treatment efficacy of Taraxacum with Dongchimi fermentation and investigate Taraxacum's effects on protection of liver cell and controlling nitric oxide(NO) through experiments, thus checking whether it had values as a physiological active matter. The experimental materials include Taraxacum Dongchimi (TD) and Taraxacum fermented by Dongchimi (TDF). As for methodology, experiments were carried out to compare TD and TDF in components, protection effects for liver cells, anticancer effects on liver cells, and protection effects for brain cells in the aspects of liver function and immunity enhancement. Method : The experimental materials include Taraxacum Dongchimi (TD) and Taraxacum fermented by Dongchimi (TDF). As for methodology, experiments were carried out to compare TD and TDF in components, protection effects for liver cells, anti-cancer effects on liver cells, and protection effects for brain cells in the aspects of liver function and immunity enhancement. Results : As shown in the chromatogram results, each valid component content increased in Taraxacum fermented by Dongchimi (TDF) for each time section. Of them, the valid component content at 36.80 minutes was approximately 2.7 times higher in TDF at 21.8% than in Taraxacum Dongchimi (TD) at 8.28%. TDF generated more excellent protection effects against the toxicity that caused oxidative damage to the liver cell(HepG2) with t-BHP than TD. The survival rate was low in TD of $100{\mu}g/m{\ell}$ and $300{\mu}g/m{\ell}$ and increased to 23.3% in TDF of $100{\mu}g/m{\ell}$. The survival rate was the highest at $300{\mu}M$ with a significant difference of 68.1%(P<0.05). Both TD and TDF showed effects of controlling nitric oxide production according to concentration with TDF recording a higher rate of controlling nitric oxide production than TD. There were significant differences(P<0.05) in the effects of controlling nitric oxide production at 200 ug/ml, 400 ug/ml in both groups. Especially the result TDF of $400{\mu}g/m{\ell}$ was thus similar to those of butein, the positive control group. Conclusion : The result of this studies is that Taraxacum fermented by Dongchimi (TDF) increased the valid component content compared with the simple mixture(TD). The findings clearly show that it is a material with the effects of improving immunity and liver cell protection. If fermentation methods are further developed to use it as a functional material, it will be subject to more opportunities of being used in other functional foods and make a contribution to integrated medicinal food development.

• Proceedings of the Korean Institute of Surface Engineering Conference
• /
• 2016.11a
• /
• pp.202-202
• /
• 2016

API X-80강재의 수소유기균열(HIC)현상을 비파괴적으로 평가하는 장치를 구축하고 금상학적 평가를 수행하였다. 시편은 열간 압연된 API X-80강재이며 평균입도는 약 $1.76-1.99{\mu}m$ 이었다. 압연재의 금상학적 집합조직은 (110)극점은 ND방향에 평행, (100)극점은 TD방향으로 약 $30^{\circ}$, TD방향으로부터 RD방향으로 약 $45^{\circ}$ 기울어져 있으며, (211)면은 RD방향에 수직인 면으로부터 TD방향으로 약 $35^{\circ}$ 기울어져서 있었다. Pin-on-disk형 마모시험기를 이용한 상온 평균 마찰계수는 0.745였으며 마모손실은 0.0196 mm/min 이었다. 3축 제어 초음파 비파괴 검사 장비는 표면으로부터 약 3mm 깊이의 1 mm 크기의 모의 균열을 탐촉자가 10 mm 접근하면 검출이 가능하였다. HIC시험분위기(NACE-standard TM 0248)에 1일 이상 장입하면 초음파비파괴검사장비로 측정될 수 있는 마이크로미터크기의 균열을 측정할 수 있었다.