• 대기
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• 제29권4호
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• pp.501-509
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• 2019

Asian Dust is a meteorological phenomenon that sand particles are raised from the arid and semi-arid regions-Taklamakan Desert, Gobi Desert and Inner Mongolia in China-and transported by westerlies and deposited on the surface. Asian dust results in a negative effect on human health as well as environmental, social and economic aspects. For monitoring of Asian Dust, Korea Meteorological Administration operates 29 stations using a continuous ambient particulate monitor. Kim et al. (2016) developed an automatic quality check (AQC) algorithm for objective and systematic quality check of observed PM₁₀ concentration and evaluated AQC with results of a manual quality check (MQC). The results showed the AQC algorithm could detect abnormal observations efficiently but it also presented a large number of false alarms which result from valid error check. To complement the deficiency of AQC and to develop an AQC system which can be applied in real-time, AQC has been modulated. Based on the analysis of instrument status codes, valid error check process was revised and 6 status codes were further considered as normal. Also, time continuity check and spike check were modified so that posterior data was not referred at inspection time. Two-year observed PM₁₀ concentration data and corresponding MQC results were used to evaluate the modulated AQC compared to the original AQC algorithm. The results showed a false alarm ratio decreased from 0.44 to 0.09 and the accuracy and the probability of detection were conserved well in spite of the exclusion of posterior data at inspection time.

• Environmental Engineering Research
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• 제11권5호
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• pp.277-284
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• 2006

The genetic toxicity of environmental pollutants, namely, nonylphenol (NP), bisphenol A (BPA) and chloropyriphos (CP) was investigated in aquatic sentinel species, freshwater crustacean, Daphnia magna, and larva of aquatic midge, Chironomus tentans, using Comet assay. Physiological effect of such pollutants was also investigated by studying the specimens' rates of reproduction, growth and survival. Acute toxicity results showed that, as expected, Daphnia was more sensitive than Chironomus to chemical exposure. The order of acute toxicity was CP > NP > BPA in D. magna and NP > CP > BPA in C. tentans. BPA may exert a genotoxic effect on D. magna and C. tentans, given that DNA strand breaks increased in both species exposed to this compound, whereas NP- and CP-induced DNA damage occurred only in C. tentans. In vivo genotoxic data obtained in aquatic sentinel species could provide valuable information for freshwater quality monitoring. The experiments with NP-exposed D. magna showed that the pollutant has long-term effects on reproduction, whereas no short-term effect on DNA integrity was found, being an example of a false-negative result from the biomarkers perspective. This result could be interpreted that other mechanism than genetic alteration might be involved in NP-induced reproduction failure in D. magna. False-positive results from the genotoxic biomarker obtained in BPA-exposed D. magna and in NP-exposed C. tentans make it difficult to use DNA integrity as an early warning biomarker. However, as the mere presence of genotoxic compounds, which are potentially carcinogenic, is of high concern to human and ecosystem health, it could also be important to rapidly and effectively detect genotoxic compounds in the aquatic system in ways that do not necessarily accompany a higher level of alteration. Considering the potential of D. magna and C. tentans as bioindicator species, and the importance of genotoxic biomarkers in ecotoxicity monitoring, DNA damage in these species could provide useful information for environmental risk assessment.

• Asian Pacific Journal of Cancer Prevention
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• 제15권1호
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• pp.423-426
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• 2014

Aim: To evaluate the agreement between colposcopic diagnosis and cervical pathology a retrospective chart review was performed. Materials and Methods: This study included 437 patients who underwent colposcopy and cervical biopsy or conization at Siriraj Hospital from October 2010 - December 2012. The patient clinical characteristics, cervical cytology results, colposcopic diagnoses, cervical pathology results were recorded and correlations between variables were analyzed. Results: Agreement of colposcopic diagnosis and cervical pathology was matched in 253 patients (57.9%). The strength of agreement with weighted Kappa statistic was 0.494 (p<0.001). Colposcopic diagnoses more often overestimated (31.1%) than underestimated (11%) the cervical pathology. Agreement of colposcopic diagnosis and cervical pathology within 1 grade was found in 411 patients (94.1%). Positive predictive value (PPV) of high grade colposcopy or more was 75.5%, whereas the negative predictive value (NPV) of insignificant and low grade colposcopy was 83.8%. False positives of high grade colposcopy or more were 21%. False negatives of insignificant or low grade colposcopy were 19.1%. Conclusions: Strength of agreement between colposcopic diagnosis and cervical pathology was found to be only moderate. A biopsy at colposcopy should be performed at a gold standard level to detect high grade lesions.

• The Korean Journal of Physiology and Pharmacology
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• 제21권5호
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• pp.555-563
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• 2017

Electrical stimulation through retinal prosthesis elicits both short and long-latency retinal ganglion cell (RGC) spikes. Because the short-latency RGC spike is usually obscured by electrical stimulus artifact, it is very important to isolate spike from stimulus artifact. Previously, we showed that topographic prominence (TP) discriminator based algorithm is valid and useful for artifact subtraction. In this study, we compared the performance of forward backward (FB) filter only vs. TP-adopted FB filter for artifact subtraction. From the extracted retinae of rd1 mice, we recorded RGC spikes with $8{\times}8$ multielectrode array (MEA). The recorded signals were classified into four groups by distances between the stimulation and recording electrodes on MEA (200-400, 400-600, 600-800, $800-1000{\mu}m$). Fifty cathodic phase-$1^{st}$ biphasic current pulses (duration $500{\mu}s$, intensity 5, 10, 20, 30, 40, 50, $60{\mu}A$) were applied at every 1 sec. We compared false positive error and false negative error in FB filter and TP-adopted FB filter. By implementing TP-adopted FB filter, short-latency spike can be detected better regarding sensitivity and specificity for detecting spikes regardless of the strength of stimulus and the distance between stimulus and recording electrodes.

• 한국컴퓨터산업학회논문지
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• 제6권5호
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• pp.715-724
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• 2005

최근 들어 폐쇄 환경에서 동작하던 많은 주요 시스템들이 웹 서비스를 제공하면서 호스트는 물론 제공되는 웹기반의 서비스들이 쉽게 공격의 주요 대상이 되고 있다. 뿐만 아니라 웹 컨텐츠나 어플리케이션의 다양성은 새로운 공격 기술을 개발하는 원인이 되기도 한다. 반면 기존의 오용기반 탐지 기법으로는 공격 기술의 발전 속도를 따라가지 못할 뿐더러 새로운 보안 위협을 처리하는 능력이 없다. 따라서 기존의 공격 유형과 함께 새롭게 개발되는 공격과 침입을 탐지하고 대처할 수 있는 기술이 연구되고 개발되고 있다. 본 논문에서는 HTTP 트래픽 패턴과 패킷 정보를 분석하여 HTTP 트래픽 모델에서의 비정상 행위 발생을 실험하였으며, 그 실험 결과를 적용하여 비정상행위를 탐지 가능한 HTTP 트래픽 모델을 설계하고 구현하였다.

• Journal of Information Processing Systems
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• 제3권2호
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• pp.43-53
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• 2007

The use of agent paradigm in today's applications is hampered by the security concerns of agents and hosts alike. The agents require the presence of a secure and trusted execution environment; while hosts aim at preventing the execution of potentially malicious code. In general, hosts support the migration of agents through the provision of an agent server and managing the activities of arriving agents on the host. Numerous studies have been conducted to address the security concerns present in the mobile agent paradigm with a strong focus on the theoretical aspect of the problem. Various proposals in Intrusion Detection Systems aim at securing hosts in traditional client-server execution environments. The use of such proposals to address the security of agent hosts is not desirable since migrating agents typically execute on hosts as a separate thread of the agent server process. Agent servers are open to the execution of virtually any migrating agent; thus the intent or tasks of such agents cannot be known a priori. It is also conceivable that migrating agents may wish to hide their intentions from agent servers. In light of these observations, this work attempts to bridge the gap from theory to practice by analyzing the security mechanisms available in Aglet. We lay the foundation for implementation of application specific protocols dotted with access control, secured communication and ability to detect tampering of agent data. As agents exists in a distributed environment, our proposal also introduces a novel security framework to address the security concerns of hosts through collaboration and pattern matching even in the presence of differing views of the system. The introduced framework has been implemented on the Aglet platform and evaluated in terms of accuracy, false positive, and false negative rates along with its performance strain on the system.

• 대한세포병리학회지
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• 제10권2호
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• pp.133-143
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• 1999

Fine needle aspiration cytology of the salivary lesions was performed on 221 patients at Soonchunhyang University Hospital for 10 years. Of 221 aspirates, 6 aspirates(2.7%) were inadequate, 116 cases(52.5%) were non-neoplastic lesions, 76(34.4%) cases were benign neoplasms and 23 cases(10.4%) were malignant neoplasms. The cytologic diagnoses could be correlated with histologic findings in 58 cases. FNAC correctly discriminated between neoplastic and nonneoplastic lesions in fifty-seven lesions and failed in a case, and overall accuracy, sensitivity, and specificity were 98.3%, 98.0%, and 100.0%. FNAC correctly discriminated malignant neoplasms from benign neoplastic/nonneoplastic lesions in fifty-three cases and fatted in five cases, and overall accuracy, sensitivity, and specificity were 91.3%, 72.7%, and 95.7%. Among three false negative cases, two mucoepidermoid carcinomas were misdiagnosed as mucocele and benign neoplasm, and an acinic cell carcinoma were misdiagnosed as Warthin's tumor. Two false positive cases were a Warthin's tumor misdiagnosed as squamous cell carcinoma and a pleomorphic adenoma misinterpretated as suggestive of malignancy. In conclusion diagnostic accuracy of FNAC of salivary lesions is high, and the possibilities of low grade mucoepidermoid carcinoma and acinic cell carcinoma should be considered on hypocellular smears with mucoid or fluidy background.

• 대한세포병리학회지
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• 제10권1호
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• pp.13-19
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• 1999

The authors analysed 2,653 cases of transthoracic fine needle aspiration cytology of the lung to evaluate the diagnostic accuracy and its limitation. A comparison was made between the original cytologic and the final histologic diagnoses on 1,149 cases from 1,074 patients. A diagnosis of malignancy was established in 38.3% benign in 48.1%, atypical lesion in 2.3%, and inadequate one in 11.9% of the cases. Statistical data on cytologic diagnoses were as follows; specificity 98.9%: sensitivity of procedure, 76.8%: sensitivity of diagnosis, 95.5%: false positive 5 cases: false negative 18 cases: predictive value for malignancy, 98.8%: predictive value for benign lesion, 79.5%: overall diagnostic efficiency, 87.5%: typing accuracy in malignant tumor, 80%.

• 대한세포병리학회지
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• 제4권2호
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• pp.111-120
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• 1993

Fine needle aspiration cytology has become a frequently used technique for the diagnosis of lesions in the head and neck. Fine needle aspiration cytology of the salivary glands were performed on 66 patients. In 59 patients with satisfactory samples, cytologic diagnoses were as follows; there were 47 benign lesions, including pleomorphic adenoma(20), Warthin's tumor(3), benign cystic lesion(4), Inflammatory lesion(4), lymphoid lesion(3), myoepithelioma(1), unspecified benign neoplasm (5), and unclassified benign lesion(7). There were 6 cases of undetermined malignancy and 6 malignant lesions including mucoepidermoid carcinoma(3), adenoid cystic carcinoma(1), carcinoma ex pleomorphic adenoma(1), and metastatic carcinoma(1) in cytologic diagnosis. In 25 patients, the cytologic diagnosis was correlated with histologic findings. The sensitivity of the benign lesion was 96% and the specificity was 82%. There was no false-positive diagnosis. The sensitivity and the specificity of pleomorphic adenoma were 75% and 95%, respectively. Some of Warthin's tumors were confused with benign cystic lesion due to frequent cystic change of the tumor. The sensitivity and specificity of the malignant lesions were 56% and 88%, respectively. There were three false negative diagnoses. Two mucoepidermoid carcinomas were correctly diagnosed by cytology. Two of three adenoid cystic carcinomas were misdiagnosed as benign tumors.

• 대한의생명과학회지
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• 제21권1호
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• pp.9-14
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• 2015

Mouse hepatitis virus (MHV) is a major pathogen in laboratory mice that usually leads to fatal diseases, such as hepatitis, multiple sclerosis, encephalitis, and respiratory disease. MHV has a high infection rate, and it needs to be detected as soon as possible to prevent its spread to other facilities. However, MHV detection by enzyme-linked immunosorbent assay (ELISA) often gives false positives; thus, it is very important that the results are confirmed as true positives in the early infection stage or distinguished as false positives with more accurate, reliable methods. Under microbiological screening, MHV ELISA-positive mice were found in four GFP-tagging transgenic mice. To verify the detection of the MHV antigen directly, reverse transcription polymerase chain reaction (RT-PCR) was performed, and the mice were determined to be MHV negative. Additional serum antibody-based screening was conducted with three different ELISA kits, and multiplexed fluorometric immunoassay (MFIA) was performed to confirm their accuracy/sensitivity. In brief, the ELISA kit for A59 nucleocapsid protein (MHV-A59N) revealed MHV ELISA positivity, while other ELISA kits (MHV-S lysate and MHV-JHM lysate) demonstrated MHV negativity. In MFIA, only the test for the recombinant A59 nucleocapsid antigen was MHV positive, which was consistent with the ELISA results. These results suggest that the ELISA kit with the recombinant A59 nucleocapsid antigen might induce non-specific MHV ELISA positivity and that confirmation is therefore essential.