• Journal of Internet Computing and Services
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• v.10 no.5
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• pp.27-32
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• 2009

Colored thread algorithm, suggested to be used for the label switching network, needs to be modified for the packet switching network. In this paper, it is recommended to add a merged state, besides the 3 states - null, colored and transparent - which are resulted from the behaviors of extend, rewind, stall, withdraw and merge events. The original colored thread algorithm is designed to generate a new thread and extend it to the downstream direction with unknown hop count when the thread has revisited the node that was visited. It also suggested rewinding the thread to the downstream direction by the source node, instead of rewinding it upstream direction by the revisited node. If a node received multiple threads which had a same forward equivalent class, then it checks first whether the hop counts are ascending or not. If it is in ascending order, then threads are merged. Otherwise the later thread is stalled until the former thread's color is to be changed to transparent or it is removed. This idea removes the effort of generating a new thread with unknown hop count.

• Journal of Chest Surgery
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• v.54 no.3
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• pp.191-199
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• 2021

Background: Tracheal replacement is a challenge for thoracic surgeons due to stenosis in the trachea-prosthesis anastomosis. We propose that stenosis occurs due to fibrosis as a result of an abnormal healing process, characterized by an increased expression of wound healing growth factors (vascular endothelial growth factor [VEGF], survivin, and CD31), which promote angiogenesis and decrease apoptosis. We analyzed the immunoreactivity of VEGF, survivin, CD31, and caspase-3 in the development of fibrotic stenosis in prosthetic tracheal replacement. Methods: Fourteen dogs were operated on: group I (n=7) received a 6-ring cervical tracheal segment autograft, while in group II (n=7), a 6-ring segment of the cervical trachea was resected and tracheal continuity was restored with a Dacron prosthesis. The follow-up was 3 months. Immunoreactivity studies for VEGF, survivin, CD31, and caspase-3 were performed. A statistical analysis was done using the Wilcoxon signed rank test. Results: Four animals in group I were euthanized on the 10th postoperative day due to autograft necrosis. Three animals completed the study without anastomotic stenosis. Moderate expression of VEGF (p=0.038), survivin (p=0.038), and CD31 (p=0.038) was found. All group II animals developed stenosis in the trachea-prosthesis anastomotic sites. Microscopy showed abundant collagen and neovascularization vessels. Statistically significant immunoreactive expression of VEGF (p=0.015), survivin (p=0.017), and CD31 (p=0.011) was observed. No expression of caspase-3 was found. Conclusion: We found a strong correlation between fibrosis in trachea-prosthesis anastomoses and excessive angiogenesis, moderate to intense VEGF, CD31, and survivin expression, and null apoptotic activity. These factors led to uncontrolled collagen production.

• International Journal of Knowledge Content Development & Technology
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• v.11 no.1
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• pp.49-64
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• 2021

This research paper delved into the availability and utilization of library portal services for research in university libraries in Nigeria. Two research questions and two null hypotheses were formulated to guide the study. A structured questionnaire was used for data collection. The study was carried out in Nnamdi Azikiwe Library, University of Nigeria Nsukka (UNN) and Felix Aghagbo Nwako Library, Nnamdi Azikiwe University Library (UNIZIK), Awka. A total of 70 professionals (librarians and system analysts) in these libraries supplied data for the study. Data collected was analyzed using mean and standard deviation. These were used to answer the research questions while the null hypotheses were tested using t-test statistic at 0.05 level of significance and 68 degree of freedom. Major findings showed that portal services available in the library showed that the areas of availability of library portal services in Nnamdi Azikiwe Library, U.N.N. includes Agriculture, Health Sciences, Engineering, Environmental Sciences and information about institution, Social Sciences, Arts and Humanities, Natural Sciences. In Festus Aghagbo Nwako Library, Awka, the areas of Portal Library Services include Career Development, Federal Government Programs, Environmental Sciences, Biological Sciences, Social Sciences, Arts and Humanities, Engineering, and Health Sciences. Findings on extent of utilization of portal services available in the libraries indicated that portal services are utilized to a low extent in the university libraries. Furthermore, librarians did not significantly differ in their opinions on the availability of library portal services and on the extent of utilization of library portal services in the libraries under study. It is therefore recommended that provisions should be made by the universities and library management to provide and update required portal services in addition to creating enabling environment for enhanced access and utilization of these services. The governments must make an effort to provide funds for policy implementation, necessary technology training for librarians and users, and develop general information infrastructure.

• Korean Journal of Remote Sensing
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• v.37 no.4
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• pp.777-788
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• 2021

Since aerosol has a relatively short duration and significant spatial variation, satellite observations become more important for the spatially and temporally continuous quantification of aerosol. However, optical remote sensing has the disadvantage that it cannot detect AOD (Aerosol Optical Depth) for the regions covered by clouds or the regions with extremely high concentrations. Such missing values can increase the data uncertainty in the analyses of the Earth's environment. This paper presents a spatial gap-filling framework using a univariate statistical method such as DCT-PLS (Discrete Cosine Transform-based Penalized Least Square Regression) and FMM (Fast Matching Method) inpainting. We conducted a feasibility test for the hourly AOD product from AHI (Advanced Himawari Imager) between January 1 and December 31, 2019, and compared the accuracy statistics of the two spatial gap-filling methods. When the null-pixel area is not very large (null-pixel ratio < 0.6), the validation statistics of DCT-PLS and FMM techniques showed high accuracy of CC=0.988 (MAE=0.020) and CC=0.980 (MAE=0.028), respectively. Together with the AI-based gap-filling method using extra explanatory variables, the DCT-PLS and FMM techniques can be tested for the low-resolution images from the AMI (Advanced Meteorological Imager) of GK2A (Geostationary Korea Multi-purpose Satellite 2A), GEMS (Geostationary Environment Monitoring Spectrometer) and GOCI2 (Geostationary Ocean Color Imager) of GK2B (Geostationary Korea Multi-purpose Satellite 2B) and the high-resolution images from the CAS500 (Compact Advanced Satellite) series soon.

• Asian Pacific Journal of Cancer Prevention
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• v.15 no.15
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• pp.6131-6136
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• 2014

Objective: Epidemiology studies have reported conflicting results between glutathione S-transferase Mu-1 (GSTM1), glutathione S-transferase theta-1 (GSTT1) and glutathione S-transferase pi-1 (GSTP1) and ovarian cancer (OC) susceptibility. In this study, an updated meta-analysis was applied to determine whether the deletion of GSTM1, GSTT1 and GSTP1 has an influence on OC susceptibility. Methods: A published literature search was performed through PubMed, Embase, Cochrane Library, and Science Citation Index Expanded database for articles published in English. Pooled odds ratios (ORs) and 95% confidence intervals (95%CIs) were calculated using random or fixed effects models. Heterogeneity between studies was assessed using the Cochrane Q test and $I^2$ statistics. Sub-group analysis was conducted to explore the sources of heterogeneity. Sensitivity analysis was employed to evaluate the respective influence of each study on the overall estimate. Results: In total, 10 published studies were included in the final analysis. The combined analysis revealed that there was no significant association between GSTM1 null genotype and OC risk (OR=1.01, 95%CI: 0.91-1.12). Additionally, there was no significant association between GSTT1 genetic polymorphisms and OC risk (OR=0.98, 95% CI: 0.85-1.13). Similalry, no significant associations were found concerning the GSTP1 rs1695 locus and OC risk. Meanwhile, subgroup analysis did not show a significant increase in eligible studies with low heterogeneity. However, sensitivity analysis, publication bias and cumulative analysis demonstrated the reliability and stability of the current meta-analysis. Conclusions: These findings suggest that GSTs genetic polymorphisms may not contribute to OC susceptibility. Large epidemiological studies with the combination of GSTM1 null, GSTT1 null and GSTP1 Ile105Val polymorphisms and more specific histological subtypes of OC are needed to prove our findings.

• Journal of Korea Port Economic Association
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• v.25 no.2
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• pp.115-128
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• 2009

This study aims to identify the influence of exchange rate and national economy on Export through container ports (Busan Port, Incheon Port, Gwangyang Port, and Pyeongtaek Port) from January 2001 to October 2007. This study carried a unit root test on the results of the analysis and failed to reject the null hypothesis that level variables have a unit root at the level of 1%. However, it carried out a unit root test on the variables by the first order difference and succeeded in rejecting the null hypothesis aforementioned at the level of 1%. As a result of the cointegration test, it was found that the model is stable. When this study carried out a variance decomposition on the prediction error of export at container various container ports, it found 89% for Busan Port, 83% for Incheon Port, 86% for Gwangyang Port, and 84% for Pyeongtaek Port. These figures indicate that such variables significantly account for export at container ports. For Busan Port, Step 2 of exchange rate showed negative (-) effect, and Step 3 shows an extreme transition into a positive (+) effect. The national economy showed an extreme change from Steps 2 to Step 7, and then a positive effect has been maintained. The Incheon Port, Gwangyang Port and Pyeongtaek Port showed similar trends to Busan Port. From Step 7, it seems that they have Shifted to more stable trends.

• ETRI Journal
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• v.24 no.6
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• pp.435-442
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• 2002

Antenna Passive Intermodulation (PIM) level measurement results are rarely credited to be due to external signal receiving characteristics of the antennas or serious effects from external PIM sources, such as the anechoic chamber absorber and antenna tower. This paper presents an antenna PIM model for a reflected PIM measurement method. Based on the findings of null point generation and the behavior of the third order PIM values obtained by theoretical predictions and experimental results, we concluded that the results of the antenna PIM level test were influenced by the external PIM sources generated by the anechoic chamber absorber and the path differences of PIM signals coming into the antenna.

• Proceedings of the IEEK Conference
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• 2003.07c
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• pp.2749-2752
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• 2003

Magnetocardiography is a very weak biomagnetic field generated from the heart. Since the magnitude of the biomagnetic field is in the order of a few pico Tesla, it is measured with a superconducting quantum interference device (SQUID). SQUID is a transducer converting magnetic flux to voltage, however, its range of linear conversion is very restricted. In order to overcome the narrow dynamic range. a flux locked loop is used to feedback the output field with opposite polarity to the input field so that the total Held becomes zero. This prevents the operating point of the SQUID from moving too far away from the null point thereby escape from the linear region. In this paper, an emulator for the SQUID sensor and feedback coil is proposed. Magnetic courting between the original field and the generated field by the feedback coil is emulated by electronic circuits. By using the emulator, FLL circuits are analyzed and optimized without SQUID sensors. The emulator may be used as a test signal for multi-channel gain calibration and system maintenance.

• 연구논문집
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• s.34
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• pp.69-77
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• 2004

Electro-pneumatic servo valve is an electro-mechanical device which converts electric signals into a proper pneumatic flow rate or pressure. In order to improve the overall performance of pneumatic servo systems, electro-pneumatic servo valves are required, which have fast dynamic characteristics, no air leakage at a null point, and can be fabricated at a low-cost. The objective of this research is to design and to fabricate a new electro-pneumatic servo valve which satisfies the above-mentioned requirements. In order to design the mechanism of the servo valve optimally, the flow inside the valve depending upon the position of spool was analyzed variously, and on the basis of such analysis results, the valve mechanism, which was formed by combination of the spool and the sleeve, was designed and manufactured. Further, the performance of pneumatic servo valve has been verified through an overall performance test on the developed product.

• Communications for Statistical Applications and Methods
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• v.10 no.3
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• pp.749-764
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• 2003

In this paper we explain that normal theory likelihood-ratio tests(z, t, $x^2$. F) for mean(s) or variance(s) can be geometrically related to volume of difference of two joint pdf's. One is an estimated joint pdf under null parameter space $\omega$ and the other is an estimated joint pdf under full parameter space $\Omega$. For explanations, ‘distance between two distributions’ is defined. We study properties of it, and derive some results on the distance between two multivariate normal distributions.