• 한국통신학회논문지
• /
• 제24권7B호
• /
• pp.1322-1330
• /
• 1999

B-ISDN과 같은 초고속 네트워크에서 전송오류의 주요원인은 과잉밀집 상태에 있어서의 버퍼 오버플로우이며 이로 인해 셀 손실을 야기한다. 기존의 통신 프로토콜은 손실된 패킷이나 전송에러들을 다루기 위해 ARQ와 같이 오류회복을 위해 재전송 기법을 사용하고 있으나 이러한 ARQ 방법들은 재전송으로 인한 전송 지연시간이 매우 크기 때문에 초고속 네트워크에서는 적합하지 않다. 따라서 본 논문은 이러한 문제를 줄이기 위하여 B-ISDN에서 FEC를 이용한 셀손실 회복기법을 제안하였다. 제안된 기법은 새로운 순서번호(SN)인 SN*를 이용하여 연속적인 셀손실을 식별한다. SN*는 SN이외에 다른 두 개의 필드(ST, LI)를 조합하여 생성한 순서번호로 그 특성에 따라 가산적(additive) SN*와 승산적(multiplicative) SN*로 구분된다.이러한 연구결과로 FEC는 네트워크 노드상에 버퍼 오버플로우로 인한 셀손실이 발생한 경우에 유용하며 B-ISDN과 같은 초고속 통신망에서의 셀손실 회복에 효과적으로 사용할 수 있는 오류에 기법임을 보여주고 있다. 본 논문에서 제안된 효율적인 셀손실 회복기법은 향후 ATM 네트워크에서의 우선순위 제어, 과잉밀집 제어 등의 연\ulcorner에 효율적으로 사용될 수 있다.

• 한국정보통신학회논문지
• /
• 제22권5호
• /
• pp.772-778
• /
• 2018

컴퓨팅, 통신, 그리고 미세 전자기계 기술의 최근 발달로 인하여 무선 센서 네트워크 응용들이 군사용으로부터 물체 추적, 화재 탐지, 그리고 차량 센서 네트워크와 같은 많은 상업적인 분야로 확산되고 있다. 어떤 응용들에서는 WSNs를 구성하고 있는 센서 노드들이 모니터링 지역에서 생산한 버스티한 데이터를 최종 목적지인 싱크 노드까지 제한된 시간 내에 전달해야 하는 경우가 있다. 본 논문에서는 제한된 시간 내에 버스티 패킷을 전달해야 하는 응용에 적합한 BTF-MAC을 제안한다. BTF-MAC 프로토콜은 동기식 듀티 사이클 MAC 프로토콜이며, 슬롯 예약 및 데이터 트래픽에 적응적으로 동작 구간을 확대하는 메커니즘을 가진다. 성능 분석 결과 BTF-MAC 프로토콜이 관련 프로토콜인 DW-MAC이나 SR-MAC 등에 비해 에너지 소모나 전송지연 비교에서 훨씬 우수한 결과를 보여준다.

• 한국항행학회논문지
• /
• 제21권2호
• /
• pp.155-162
• /
• 2017

최근 국내에서 항공 관련 안전필수시스템들이 개발되었지만 이들 완성품들은 규정된 요구사항들을 충족시키지 못하여 실용화 또는 상용화 되지 못하였다. 현대 항공 기술의 복잡도가 높아짐에 따라 기존의 검증 및 확인 기술로는 시스템에 잠재된 리스크를 식별하고 줄이는데 어려움이 많다. 이러한 단점들을 극복하기 위해 선진국에서는 독립적 검증 및 확인이라는 새로운 기법에 관심이 모아지고 있다. 이 독립적 검증 및 확인의 효과도에 관한 학술적 연구는 국내에는 전무하고, 국외에서 조차도 매우 희소하게 수행되고 있다. 따라서 본 논문에서는 항공선진기관에서 수행한 항공 안전필수시스템에 대한 독립적 검증 및 확인의 응용 연구들을 조사하여 사업에 미치는 여러 가지 효과들을 분석해 본 결과, IV&V는 조기 오류 검출율을 높이고, 내재된 리스크도 조기에 완화하며, 개발 수명주기 후반에 나타나는 재작업 확률을 줄여서 개발 일정 및 비용의 증가를 획기적으로 막아주는 것으로 나타났다.

• Asian Pacific Journal of Cancer Prevention
• /
• 제16권11호
• /
• pp.4623-4628
• /
• 2015

Breast cancer still remains as the most frequent cancer with second mortality rate in women worldwide. There are no validated biomarkers for detection of the disease in early stages with effective power in diagnosis and therapeutic approaches. Cancer/testis antigens are recently promising tumor antigens and suitable candidates for targeted therapies and generating cancer vaccines. We conducted the present study to analyze transcript changes of two cancer/testis antigens, OIP5 and TAF7L, in breast tumors and cell lines in comparison with normal breast tissues by quantitative real time RT-PCR for the first time. Significant over-expression of OIP5 was observed in breast tumors and three out of six cell lines including MDA-MB-468, T47D and SKBR3. Not significant expression of TAF7L was evident in breast tumors but significant increase was noted in three out of six cell lines including MDA-MB-231, BT474 and T47D. OIP5 has ssignificant role in chromatin organization and cell cycle control during cell cycle exit and normal chromosome segregation during mitosis and TAF7L is a component of the transcription factor IID, which is involved in transcription initiation of most protein coding genes. TAF7Lis located at X chromosome and belongs to the CT-X gene family of cancer/testis antigens which contains about 50% of CT antigens, including those which have been used in cancer immunotherapy.

• 한국소음진동공학회:학술대회논문집
• /
• 한국소음진동공학회 2012년도 춘계학술대회 논문집
• /
• pp.447-452
• /
• 2012

Among the various elements affecting a customer's evaluation of automobile quality, buzz, squeak and rattle (BSR) are considered to be major factors. In most vehicle manufacturers, the BSR problems are solved by find-fix method with the vehicle road test, mainly due to various excitation sources, complex generation mechanism and subjective response. The aim of this paper is to develop the integrated experimental method to systematically tackle the BSR problems in early stage of the vehicle development cycle by resolving these difficulties. To achieve this aim, the developed experimental method ought to include the following requirements: to find and fix the BSR problem for modules instead of a full vehicle in order to tackle the problem in the early stage of the vehicle development cycle; to develop the exciter system including the zig and road-input-signal reproducing algorithm; to automatically localize the source region of BSR; to develop sound quality index that can be used to assess the subjective responses to BSR. Also, the BSR sound quality indexes based on the Zwicker's sound quality parameters using a multiple regression analysis. The four sound metrics from Zwicker's sound quality parameter are computed for the signals recorded for eight BSR noise source regions localized by using the acoustic-field visualized results. Then, the jury test of BSR noise are performed for participants. On a basis of the computed sound metrics and jury test result, sound quality index is developed to represent the harsh of BSR noise. It is expected that the developed BSR detection system and sound quality indexes can be used to reduce the automotive interior BSR noise in terms of subjective levels as well as objective levels.

• BMB Reports
• /
• 제38권4호
• /
• pp.391-398
• /
• 2005

3-hydrogenwadaphnin (3-HK) is a new daphnane-type diterpene ester isolated from Dendrostellera lessertii with strong anti-tumoral activity in animal models and in cultures. Here, prolonged effects of this new agent on proliferation and viability of several different cancerous cell lines were evaluated. Using [$^3H$]thymidine incorporation, it was found that the drug inhibited cell proliferation and induced G1/S cell cycle arrest in leukemic cells 24 h after a single dose treatment. The cell viability of Jurkat cells was also decreased by almost 10%, 31% and 40% after a single dose treatment (7.5 nM) at 24, 48 and 72 h, respectively. The drug-treated cells were stained with acridine orange/ethidium bromide to document the chromatin condensation and DNA fragmentation. These observations were further confirmed by detection of DNA laddering pattern in the agarose gel electrophoresis of the extracted DNA from the treated cells. Treatment of K562 cells with the drug at 7.5, 15 and 30 nM caused apoptosis in 25%, 45% and 65% of the cells, respectively. Exogenous addition of $25-50\;{\mu}M$ guanosine and/or deoxyguanosine to the cell culture of the drug-treated cells restored DNA synthesis, released cell arrest at G1/S checkpoint and decreased the apoptotic cell death caused by the drug. These observations were not made using adenosine. However, the drug effects on K562 cells were potentiated by hypoxanthine. Based on these observations, perturbation of GTP metabolism is considered as one of the main reasons for apoptotic cell death by 3-HK.

• Membrane and Water Treatment
• /
• 제9권3호
• /
• pp.181-188
• /
• 2018

A sidestream contains the filtrate or concentrate from the belt filter press, filter backwash and supernatant from sludge digesters. The sidestream flow, which heads back into the sewage treatment train, is about 1-3% less than the influent flow. However, the sidestream can increase the nutrient load since it contains high concentrations of phosphorus and nitrogen. In this study, the removal of PO4-P with organic matter characteristics and bacteriological changes during the sidestream treatment via ladle furnace (LF) slag was investigated. The sidestream used in this study consisted of 11-14% PO4-P and 3.2-3.6% soluble chemical oxygen demand in influent loading rates. LF slag, which had a relatively high $Ca^{2+}$ release compared to other slags, was used to remove $PO_4-P$ from the sidestream. The phosphate removal rates increased as the slag particle size decreased 19.1% (2.0-4.0 mm, 25.2% (1.0-2.0 mm) and 79.9% (0.5-1.0 mm). The removal rates of dissolved organic carbon, soluble chemical oxygen demand, color and aromatic organic matter ($UV_{254}$) were 17.6, 41.7, 90.2 and 77.3%, respectively. Fluorescence excitation-emission matrices and liquid chromatography-organic carbon detection demonstrated that the sidestream treatment via LF slag was effective in the removal of biopolymers. However, the removal of dissolved organic matter was not significant during the treatment. The intact bacterial biomass decreased from $1.64{\times}10^8cells/mL$ to $1.05{\times}10^8cells/mL$. The use of LF slag was effective for the removal of phosphate and the removal efficiency of phosphate was greater than 80% for up to 100 bed volumes.

• Asian Pacific Journal of Cancer Prevention
• /
• 제14권2호
• /
• pp.1111-1114
• /
• 2013

Background: For early detection of renal damage during the usage of cisplatin based chemotherapy, changes in renal function should be monitored carefully. In recent years, neutrophil gelatinase-associated lipocalin, a small polypeptide molecule, has shown promise as a marker of acute renal failure. The aim of this present study was to assess possible risk prediction of cisplatin-induced nephrotoxicity using serum NGAL. Materials and Methods: A total of 34 consecutive patients with documented serum creatinine at least 24 hours before every cycle of cisplatin-based chemotherapy were included in the study. Demographic and medical data including age, performance status, tumor characteristics and comorbid diseases were collected from medical charts. Renal function was evaluated at least 48 hours before the treatment and at the end of the treatment based on the Modification of Diet in Renal Disease (MDRD) formula. Before and after cisplatin infusion serum NGAL levels were measured for the first and 3rd cycles of chemotherapy. Results: The median age of the study population was 54 (32-70) years. Fifteen patients (41.1%) were treated on an adjuvant basis, whereas 19 patients (58.9%) were treated for metastatic disease. There was no correlation of serum NGAL levels with serum creatinine (r=0.20, p=0.26) and MDRD (r=-0.12, p=0.50) and creatinine clearance-Cockcroft-Gault (r=-0.22, p=0.22) after cisplatin infusion at the end of the 3rd cycle of chemotherapy. Conclusions: In our study, serum NGAL levels were not correlated with the cisplatin induced nephrotoxicity. Further prospective studies are needed to conclude that serum NGAL level is not a good surrogate marker to predict early cisplatin induced nephrotoxicity.

• Asian Pacific Journal of Cancer Prevention
• /
• 제14권2호
• /
• pp.747-752
• /
• 2013

Oncostatin M (OSM) is a multifunctional cellular regulator acting on a wide variety of cells, which has potential roles in the regulation of gene activation, cell survival, proliferation and differentiation. Previous studies have shown that OSM can induce morphological and/or functional differentiation and maturation of many tumor cells. However, the action of OSM on the induction of differentiation of human hepatocellular carcinoma (HCC) has not been reported. Here, we investigated the effects of different concentrations of OSM on human HCC cell line SMMC-7721 growth, proliferation, cell cycling, apoptosis and differentiation in vitro. Cell growth was determined via MTT assay, proliferation by cell cycle analysis, apoptosis by flow cytometry, morphology by transmission electronic microscopy, and cell function by detection of biochemical markers. Our results demonstrated that OSM strongly inhibited the growth of SMMC-7721 cells in a dose-dependent manner, associated with decreased clonogenicity. Cell cycle analysis revealed a decreased proportion of cells in S phase, with arrest at G0/G1. The apotosis rate was increased after OSM treatment compared to the control. These changes were associated with striking changes in cellular morphology, toward a more mature hepatic phenotype, accompanied by significant reduction of the expression of AFP and specific activity of ${\gamma}$-GT, with remarkable increase in secretion of albumin and ALP activity. Taken together, our findings indicate that OSM could induce the differentiation and reduce cell viability of SMMC-7721 cells, suggesting that differentiation therapy with OSM offers the opportunity for therapeutic intervention in HCC.

• 천문학회지
• /
• 제54권4호
• /
• pp.129-137
• /
• 2021

It has been established that the acoustic mode parameters of the Sun and Sun-like stars vary over activity cycles. Since the observed variations are not consistent with an activity-related origin, even Sun-like stars showing out-of-phase changes of mode frequencies and amplitudes need to be carefully studied using other observational quantities. In order to test whether the presumed relations between the global seismic parameters are a signature of the stellar activity cycle, we analyze the photometric light curve of HD 49933 for which the first direct detection of an asteroseismic signature for activity-induced variations in a Sun-like star was made, using observations by the CoRoT space telescope. We find that the amplitude of the envelope significantly anti-correlates with both the maximum frequency of the envelope and the width of the envelope unless superflare-like events completely contaminate the light curve. However, even though the photometric proxy for stellar magnetic activity appears to show relations with the global asteroseismic parameters, they are statistically insignificant. Therefore, we conclude that the global asteroseismic parameters can be utilized in cross-checking asteroseismic detections of activity-related variations in Sun-like stars, and that it is probably less secure and effective to construct a photometric magnetic activity proxy to indirectly correlate the global asteroseismic parameters. Finally, we seismically estimate the mass of HD 49933 based on our determination of the large separation of HD 49933 with evolutionary tracks computed by the MESA code and find a value of about 1.2M_☉ and a sub-solar metallicity of Z = 0.008, which agrees with the current consensus and with asteroseismic and non-asteroseismic data.