• Proceedings of the Korean Information Science Society Conference
• /
• 2006.10d
• /
• pp.24-29
• /
• 2006

본 논문에서는 광대역 통신 방송 융합 서비스 제공을 고려한 WDM 메트로 링 망을 위한 매체 접근 제어(Medium Access Control; MAC) 프로토콜의 성능을 분석한다. 현재 인터넷은 통신 방송 융합 망으로 진화하고 있으며 다양한 트래픽 특성을 갖는 서비스가 액세스 망에서 메트로 망으로 유입되고 있다. 그러나 기존 메트로 망의 MAC 프로토콜은 이러한 망 환경 변화를 고려하지 않고 단순하고 동일한 트래픽만을 고려하여 성능을 분석하였다. 따라서 본 논문에서는 메트로 링에 연결된 액세스 노드의 입력 트래픽을 Self-Similar와 Poisson 트래픽으로 분류하여 기존 MAC 프로토콜의 성능을 분석하고 평가한다. 메트로 링 망에 연결된 액세스 노드는 이 두 종류의 트래픽 중에서 하나를 망에 유입하며 채널을 공유하는 노드 수에 따라서 다양한 트래픽 환경이 고려된다. WDM 메트로 링망의 기본 MAC 프로토콜은 CSMA/CA(Carrier Sense Multiple Access with Collision Avoidance)이며, 패킷을 빈 슬롯에 전송하고 송신지에서 패킷을 제거하는 SS (Source-Stripping) 기반으로 운용된다. 본 논문에서는 SS 방식으로 생성된 빈 슬롯을 바로 패킷 전송에 이용하는 방식과 그렇지 않은 방식을 각각 1-Persistent와 non-Persistent로 분류하고 MAC 프로토콜을 분석하여 기존 방식의 장 단점을 비교한다. 또한 전송 공정성과 처리율을 같이 고려하여 적용할 수 있는 확률 기반 p-Persistent MAC 프로토콜도 분석하였으며 시뮬레이션을 통하여 각 프로토콜을 노드 처리율, 전송 지연, 패킷 손실률, 전송 공정성 관점에서 비교하고 평가한다.y 수행을 여러 서버로 분산처리하게 함으로써 성능에 대한 신뢰성을 향상 시킬 수 있는 Load Balancing System을 제안한다.할 때 가장 효과적인 라우팅 프로토콜이라고 할 수 있다.iRNA 상의 의존관계를 분석할 수 있었다.수안보 등 지역에서 나타난다 이러한 이상대 주변에는 대개 온천이 발달되어 있었거나 새로 개발되어 있는 곳이다. 온천에 이용하고 있는 시추공의 자료는 배제하였으나 온천이응으로 직접적으로 영향을 받지 않은 시추공의 자료는 사용하였다 이러한 온천 주변 지역이라 하더라도 실제는 온천의 pumping 으로 인한 대류현상으로 주변 일대의 온도를 올려놓았기 때문에 비교적 높은 지열류량 값을 보인다. 한편 한반도 남동부 일대는 이번 추가된 자료에 의해 새로운 지열류량 분포 변화가 나타났다 강원 북부 오색온천지역 부근에서 높은 지열류량 분포를 보이며 또한 우리나라 대단층 중의 하나인 양산단층과 같은 방향으로 발달한 밀양단층, 모량단층, 동래단층 등 주변부로 NNE-SSW 방향의 지열류량 이상대가 발달한다. 이것으로 볼 때 지열류량은 지질구조와 무관하지 않음을 파악할 수 있다. 특히 이러한 단층대 주변은 지열수의 순환이 깊은 심도까지 가능하므로 이러한 대류현상으로 지표부근까지 높은 지온 전달이 되어 나타나는 것으로 판단된다.의 안정된 방사성표지효율을 보였다. $^{99m}Tc$-transferrin을 이용한 감염영상을 성공적으로 얻을 수 있었으며, $^{67}Ga$-citrate 영상과 비교하여 더 빠른 시간 안에 우수한 영상을 얻을 수 있었다. 그러므로 $^{99m}Tc$-transierrin이 감염 병소의 영상진단에 사용될 수 있을 것으로 기대된

• Journal of Veterinary Clinics
• /
• v.25 no.6
• /
• pp.482-487
• /
• 2008

This study was performed to investigate the ophthalmic findings of the Korean traditional 'Sapsaree' dogs, and to provide ophthalmic references. Five hundred forty-seven Sapsaree dogs were randomly chosen without any criteria preference. Ophthalmic examination was performed bilaterally using ocular equipments, including slit-lamp biomicroscope, tonometer, direct and indirect ophthalmoscope. The obtained data for ophthalmic findings were analysis by the multivariate linear regression model to identify effects of sex, age and hair coat type. For congenital conditions, the incidence of persistent pupillary membrane (PPM) was the most common defect and there was present 8.8 % whereas for acquired ophthalmic diseases, cataract was the most commonly observed (3.7 %) in Sapsaree dog. Other frequent ocular finding included persistent hyaloid vessel remnant (PHVR, 6.2 %) in congenital conditions, and postinflammatory retinal degeneration (PIRD, 3.1 %) and corneal dystrophy (2.4 %) in acquired ophthalmic diseases. Only one significant effect was age of the Sapsaree for PIRD (P=0.040). There are no any significant effect for sex and hair coat types. This study will provide useful guidelines to clinicians and breeders for the basic ophthalmic information on this breed.

• Journal of Platform Technology
• /
• v.9 no.3
• /
• pp.3-17
• /
• 2021

Advanced persistent threat (APT) attacks are attacks aimed at a particular entity as a set of latent and persistent computer hacking processes. These APT attacks are usually carried out through various methods, including spam mail and disguised banner advertising. The same name is also used for files, since most of them are distributed via spam mail disguised as invoices, shipment documents, and purchase orders. In addition, such Infostealer attacks were the most frequently discovered malicious code in the first week of February 2021. CDR is a 'Content Disarm & Reconstruction' technology that can prevent the risk of malware infection by removing potential security threats from files and recombining them into safe files. Gartner, a global IT advisory organization, recommends CDR as a solution to attacks in the form of attachments. There is a program using CDR techniques released as open source is called 'Dangerzone'. The program supports the extension of most document files, but does not support the extension of HWP files that are widely used in Korea. In addition, Gmail blocks malicious URLs first, but it does not block malicious URLs in mail systems such as Naver and Daum, so malicious URLs can be easily distributed. Based on this problem, we developed a 'Dangerzone' program that supports the HWP extension to prevent APT attacks, and a Chrome extension that performs URL checking in Naver and Daum mail and blocking banner ads.

• The Korean Journal of Pain
• /
• v.23 no.1
• /
• pp.1-10
• /
• 2010

Background: Recent studies indicate that reactive oxygen species (ROS) are involved in persistent pain, including neuropathic and inflammatory pain. Since the data suggest that ROS are involved in central sensitization, the present study examines the levels of activated N-methyl-D-aspartate (NMDA) receptors in the dorsal horn after an exogenous supply of three antioxidants in rats with chronic post-ischemia pain (CPIP). This serves as an animal model of complex regional pain syndrome type-I induced by hindpaw ischemia/reperfusion injury. Methods: The application of tight-fitting O-rings for a period of three hours produced CPIP in male Sprague-Dawley rats. Allopurinol 4 mg/kg, allopurinol 40 mg/kg, superoxide dismutase (SOD) 4,000 U/kg, N-nitro-L-arginine methyl ester (L-NAME) 10 mg/kg and SOD 4,000 U/kg plus L-NAME 10 mg/kg were administered intraperitoneally just after O-ring application and on the first and second days after reperfusion. Mechanical allodynia was measured, and activation of the NMDA receptor subunit 1 (pNR1) of the lumbar spinal cord (L4-L6) was analyzed by the Western blot three days after reperfusion. Results: Allopurinol reduced mechanical allodynia and attenuated the enhancement of spinal pNR1 expression in CPIP rats. SOD and L-NAME also blocked spinal pNR1 in accordance with the reduced mechanical allodynia in rats with CPIP. Conclusions: The present data suggest the contribution of superoxide, produced via xanthine oxidase, and the participation of superoxide and nitric oxide as a precursor of peroxynitrite in NMDA mediated central sensitization. Finally, the findings support a therapeutic potential for the manipulation of superoxide and nitric oxide in ischemia/reperfusion related pain conditions.

• Korean Journal of Bronchoesophagology
• /
• v.15 no.2
• /
• pp.49-56
• /
• 2009

Purpose : To evaluate the treatment outcome for patients with locally advanced, unresectable esophageal cancer treated with relatively high dose radiation therapy(RT). Materials and Methods : From January 2000 to December 2008, 32 patients with locally advanced unresectable or medically inoperable esophageal cancer were treated with radiation therapy(RT) with or without concurrent chemotherapy. Ten patients were excluded from analysis because of distant metastasis and drop off. Patient distributions according to AJCC stages II, III IVa were 7(31.8%), 12(54.6%), 3(13.6%) respectively. The locations of tumor were cervical/upper thorax 3 (13.6%), mid thorax 13(59.1%), and lower thorax/abdominal 6(27.3%), respectively. Eleven patients received RT only, and 11 patients received cisplatin based concurrent chemoradiotherapy(CCRT). Median radiation dose was 65 Gy(range 57.6~72 Gy). Results : The median follow-up was 9.1 months(range 1.9~43.8 months). The response rates for complete response, Partial response, stable disease and Persistent disease were 6(27.3%), 11(50.0%), 4(18.2%) and 1(4.5%), respectively. Two patients(9.1%) suffered from esophageal stenosis and stents were inserted. Two patients(9.1%) had Grade 3 radiation pneumonitis and one of them expired due to acute respiratory distress syndrome(ARDS) at 36 days after completion of radiation therapy. The recurrence rate was 11(50.0%). The patterns of recurrence were persistent disease and local progression in 5(22.7%), local recurrence 3(13.7%) and concomitant local and distant recurrence in 3(13.7%). The overall survival(OS) rate was 32.1% at 2 years and 21.4% at 3 years(median 12.0 months). Disease free survival(DFS) rate was 17.3% at 2 and 3 years. All patients who had no dysphagia at diagnosis showed complete response after treatment and 100% OS at 3 years(p=0.0041). The OS for above 64.8 Gy group and 64.8 Gy or below group at 3 years were 60.6% and 9.1%(p=0.1341). The response to treatment was the only significant factor affecting OS(p=0.004). Conclusion : Relatively high dose radiation therapy in unresectable esophageal cancer tended to have a better outcome without increased complication rate. Further study with more patients is warranted to justify improved result.

• Clinical and Experimental Pediatrics
• /
• v.54 no.1
• /
• pp.22-28
• /
• 2011

Purpose: To investigate the clinical characteristics of late-onset epilepsy combined with autism spectrum disorder (ASD), and the relationship between certain types of electroencephalography (EEG) abnormalities in ASD and associated neuropsychological problems. Methods: Thirty patients diagnosed with ASD in early childhood and later developed clinical seizures were reviewed retrospectively. First, the clinical characteristics, language and behavioral regression, and EEG findings of these late-onset epilepsy patients with ASD were investigated. The patients were then classified into 2 groups according to the severity of the EEG abnormalities in the background rhythm and paroxysmal discharges. In the severe group, EEG showed persistent asymmetry, slow and disorganized background rhythms, and continuous sharp and slow waves during slow sleep (CSWS). Results: Between the two groups, there was no statistically significant difference in mean age (P=0.259), age of epilepsy diagnosis (P=0.237), associated family history (P=0.074), and positive abnormal magnetic resonance image (MRI) findings (P=0.084). The severe EEG group tended to have more neuropsychological problems (P=0.074). The severe group statistically showed more electrographic seizures in EEG (P=0.000). Rett syndrome was correlated with more severe EEG abnormalities (P=0.002). Although formal cognitive function tests were not performed, the parents reported an improvement in neuropsychological function on the follow up checkup according to a parent's questionnaire. Conclusion: Although some ASD patients with late-onset epilepsy showed severe EEG abnormalities, including CSWS, they generally showed an improvement in EEG and clinical symptoms in the longterm follow up. In addition, severe EEG abnormalities tended to be related to the neuropsychological function.

• Molecules and Cells
• /
• v.25 no.4
• /
• pp.479-486
• /
• 2008

Mitogen-activated protein kinases (MAPKs) play an indispensable role in activation of the myogenic program, which is responsive to mechanical stimulation. Although there is accumulating evidence of mechanical force-mediated cellular responses, the role of MAPK in regulating the myogenic process in myoblasts exposed to cyclic stretch is unclear. Cyclic stretch induced the proliferation of C2C12 myoblasts and inhibited their differentiation into myotubes. In particular, it induced persistent phosphorylation of p38 kinase, and decreased the level of phosphorylation of extracellular-signal regulated kinase (ERK). Partial inhibition of p38 phosphorylation increased cellular levels of MyoD and p-ERK in stretched C2C12 cells, along with increased myotube formation. Treatment with $10{\mu}M$ PD98059 prevented myogenin expression in response to a low dose of SB203580 ($3{\mu}M$) in the stretched cells, suggesting that adequate ERK activation is also needed to allow the cells to differentiate into myotubes. These results suggest that cyclic stretch inhibits the myogenic differentiation of C2C12 cells by activating p38-mediated signaling and inhibiting ERK phosphorylation. We conclude that p38 kinase, not ERK, is the upstream signal transducer regulating cellular responses to mechanical stretch in skeletal muscle cells.

• Genomics & Informatics
• /
• v.2 no.2
• /
• pp.75-80
• /
• 2004

In a variety of animal species, the perinatal exposure of experimental animals to the 2,3,7,8-tetrachlorodibenzo­p-dioxin (TCDD) leads to the immune dysfunction, which is more severe and persistent than that caused by adult exposure. We report here the changes of gene expression and the identification of the marker-genes representing the dioxin exposure. The expressions of the transcripts were analyzed using the 11 K oligonucleotide­microarray from the bone marrow cells of male C57BL/6J mice after an intraperitoneal injection of $1{\mu}g$ TCDD/kg body weight at various time intervals: gestational 6.5 day(G6.5), 13.5 day(G13.5), 18.5 day(G18.5), and postnatal 3 (P3W)and 6 week (P6W). The type of self-organizing maps(SOM) representing the specific exposure dioxin could be identified as follows; G6.5D(C14), G13.5D(C0, C5, C10, C18), G18.5D(7): P3W(C2, C21), and P6W(C4, C15, C20). The candidate marker-genes were restricted to the transcripts, which could be consistently expressed greater than $\pm$2-fold in three experiments. The resulting candidates were 85 genes, the characteristics of that were involved in cell physiology and cell functions such as cell proliferation and immune function. We identified the biomarker-genes for dioxin exposure: smc -like 2 from SOM C14 for the dioxin exposure at G6.5D, focal adhesion kinase and 6 other genes from C0, and protein tyrosine phosphatase 4a2 and 3 other genes from C5 for G13.5D, platelet factor 4 from C7 for G18.5D, fos from C2 for P3W.

• Proceedings of the Korean Vacuum Society Conference
• /
• 1999.07a
• /
• pp.120-120
• /
• 1999

III-nitride계 물질들은 blue와 UV 영역의 LED, LD와 같은 광소자뿐만 아니라 HBT, FET와 같은 전자소자로도 널리 응용되고 있다. 이와 같은 물질을 이용한 소자를 제작할 수 있는 낮은 저항의 ohmic contact은 필수적이다. Al이나 Ti와 같은 물질을 기초로 한 n-GaN의 경우는 이미 많은 연구결과가 발표되어 전기적 광학적 소자를 동작하는데 충분히 낮은 ohmic contact저항( )을 었다. 그러나 p-GaN의 ohmic contact은 아직까지 많은 문제점을 내포하고 있다. 그 중의 하나는 높은 doping 농도( )의 p-GaN 박막을 성장하기가 어렵다는 것이며, 또 하나는 낮은 접촉 비저항을 얻기 위해선 7.5eV이상의 큰 재가 function을 지닌 금속을 선택해야 한다. 그러나 5.5eV 이상의 재가 function을 갖는 금속은 존재하지 않는다. 위와 같은 문제점들은 p-GaN의 접촉 비저항이 이상의 높은 값을 갖게 만들고 있으며, 이에 대한 해경방안으로는 고온의 열처리를 통하여 p-GaN와 금속 사이에서 화학적 반응을 일으킴으로써 표면 근처에서 캐리어농도를 증가시키고, 캐리어 수송의 형태가 tunneling 형태로 일어날 수 있도록 하는 tunneling current mechanism을 이용하는 것이다. 이로 인해 결국 낮은 접촉 비저항을 얻을 수 있게되며, 일반적으로 p-GaN에서는 Nidl 좋은 물질로 알려져 있다. 그러나 Ni은 50$0^{\circ}C$이상의 열처리에서 쉽게 산화되는 특성 때문에 높은 캐리어를 얻는데 어려운 문제점이 있다. 이에 본 연구에서는 MBE로 성장된 p-GaN박막을 Mg의 activation을 더욱 증가시키기 위해 N2 분위기에서 15분간 90$0^{\circ}C$에서 annealing을 하였으며, ohmic 접촉을 위한 금속으로 높은 재가 function과 좋은 adhesion 그리고 낮은 자체저항을 가지고 있는 Ni/Au를 ohmic metal로 하여 contact한 후에 90$0^{\circ}C$에서 10초간 rapid thermal annealing (RTA)처리를 했다. 성장된 박막의 광학적 성질은 PL로써 측정하였으며, photoconductivity 실험을 통해 impurity의 life time을 분석하였고, persistent photoconductivity를 통해 dark current를 측정하였다. 또한 contact resistance를 계산하기 위해 circular-TLM method을 이용하여 I-V 특성을 조사하였다.

• Journal of Digital Convergence
• /
• v.16 no.4
• /
• pp.231-249
• /
• 2018

The purpose of this study is analyze the factors affecting the standard precaution(SP) performance on the knowledge, awareness, attitude and safety environment for SP of healthcare workers of general hospitals. The research method was a descriptive research study. The subject were 262 of healthcare workers of general hospitals. The data were analyzed using descriptive statistics, t-test, Chi-square test, ANOVA, Person's correlation coefficient and Multiple regression analysis using the SPSS program. As a result of the correlation analysis SP Performance was positively correlated with attitude (r=.18, p=.003), safety environment (r=.42, p<.001) and awareness (r=.63, p<.001). As a result of the stepwise multiple regression analysis on the factors influencing SP performance were SP awareness and safety environment. Therefore, in order to improved performance of SP, it's important to improve a awareness and safety environment of SP. Different and persistent infection management educational programs that consider the occupational characteristics and monitoring are required.