1,286 research outputs found
Ck-Log, A Calculus for Knowledge Processing in Logic
No full textThis paper introduces the principal concepts in the organization and operation of the logic based knowledge processing system, called CK-LOG (A Calculus for Knowledge in Logics). CK-LOG uses the frame based system MDS (the Meta Description System) for knowledge representation and for modeling world states. It uses an inference engine based on Natural Deduction for stating and solving problems. As a knowledge processing system CK-LOG has several capabilities, which are new to the technology of knowledge representation systems: CK-LOG has special facilities to represent and reason about actions and their time dependencies. Actions that occur in a world state may create or destroy objects in the world or modify their properties, or prevent or support other actions. The effects of actions are described in CK-LOG using modal operators like CREATE, DESTROY, PREVENT, SUPPORT, KEEP, etc. These operator expressions are also used to represent and reason about possible worlds that the actions might lead to. Most significantly, CK-LOG is a logic-based knowledge processing system, just as PROLOG is logic based programming system. CK-LOG uses a three valued logical system with truth values T (true),? (Unknown) and F (false) to build partial models of world states, and the two valued logic's system of T and F in its theorem proving System. The use of the three valued logical system in its models of world states enables CK-LOG to do problem solving in the context of incomplete information about world states. The theorem proving system of CK-LOG uses a variant of the calculus of sequents first proposed by Kanger (which itself is a variant of Gentzen's system). The two variations in CK-LOG are, (i). the use of a new algorithm called the mating algorithm for testing proof terminations, and (ii) the use of specialized inference rules for reasoning about modal expressions using the possible world semantics.. The mating algorithm gives the theorem proving system of CK-LOG several new capabilities: to identify information that is pertinent to a given problem and retrieve it from its knowledge base, to update its models of possible worlds during the problem solving process based on the findings of the theorem proving system, to use these models of world states to test proof terminations, and to generate hypotheses during the problem solving process that are based on unknown information. These various features of CK-LOG are described here. The paper concludes with a discussion of the logic of frames as used in CK-LOG and establishes a condition called locality condition as a sufficient condition for creating knowledge representations with requisite completeness.Technical report DCS-TR-15
Outcomes after curative therapy for hepatocellular carcinoma in patients with non-alcoholic fatty liver disease: a meta-analysis and review of current literature
No full textHighly parallel and energy-efficient exhaustive minimum distance search engine using hybrid digital/analog circuit techniques
No full textA minimum distance search engine (MDSE) is presented as a hardware. accelerator for various exhaustive pattern-matching systems. This chip executes highly parallel computations of L-1-norms between an input query and stored multiple reference records, and searches for the minimum distance among them in a highly parallel fashion. Our architectural-level estimation shows that this MDSE can reduce energy dissipation by orders of magnitude as the number of records increases, compared with the conventional systems. We have designed a prototype 4-bit 8-word MDSE composed of merged memory logic (MML) and digital/analog-mixed winner-take-all circuit (DAM-WTAC) by using hybrid digital/analog circuit techniques. It was fabricated with a 0.6-mum single-poly triple-metal CMOS technology. Experimental results show that our chip works properly at 3 V/10 MM and has approximately four times larger throughput as well as four times higher energy efficiency, compared with the existing 8-bit microcontrollers.The author would like to thank MICROS, IDEC and Samsung Electronics
Company for their support. They would also like to thank the
reviewers for their valuable comments and Dr. K. Kim, Samsung Electronics
Company, for useful discussion
Impact of guideline adherence on the prognosis of Barcelona clinic liver cancer stage B hepatocellular carcinoma
No full textBACKGROUND: Patients with Barcelona clinic liver cancer (BCLC) stage B hepatocellular carcinoma (HCC) are considerably heterogeneous in terms of tumor burden, liver function, and performance status. To improve the poor survival outcomes of these patients, treatment approaches other than transarterial chemoembolization (TACE), which is recommended by HCC guidelines, have been adopted in real-world clinical practice. We hypothesize that this non-adherence to treatment guidelines, particularly with respect to the use of liver resection, improves survival in patients with stage B HCC.
AIM: To assess guideline adherence in South Korean patients with stage B HCC and study its impact on survival.
METHODS: A retrospective analysis was conducted using data from 2008 to 2016 obtained from the Korea Central Cancer Registry. Patients with stage B HCC were categorized into three treatment groups, guideline-adherent, upward, and downward, based on HCC guidelines recommended by the Asian Pacific Association for the Study of the Liver (APASL), the European Association for the Study of the Liver (EASL), and the American Association for the Study of Liver Diseases (AASLD). The primary outcome was HCC-related deaths; tumor recurrence served as the secondary outcome. Survival among the groups was compared using the Kaplan-Meier method and the log-rank test. Predictors of survival outcomes were identified using multivariable Cox regression analysis.
RESULTS: In South Korea, over the study period from 2008 to 2016, a notable trend was observed in adherence to HCC guidelines. Adherence to the EASL guidelines started relatively high, ranging from 77% to 80% between 2008 and 2012, but it gradually declined to 58.8% to 71.6% from 2013 to 2016. Adherence to the AASLD guidelines began at 71.7% to 75.9% from 2008 to 2010, and then it fluctuated between 49.2% and 73.8% from 2011 to 2016. In contrast, adherence to the APASL guidelines remained consistently high, staying within the range of 90.14% to 94.5% throughout the entire study period. Upward treatment, for example with liver resection, liver transplantation, or radiofrequency ablation, significantly improved the survival of patients with BCLC stage B HCC compared to that of patients treated in adherence to the guidelines (for patients analyzed according to the 2000 EASL guidelines, the 5-year survival rates were 63.4% vs 27.2%, P < 0.001), although results varied depending on the guidelines. Progression-free survival rates were also significantly improved upon the use of upward treatments in certain groups. Patients receiving upward treatments were typically < 70 years old, had platelet counts > 105/μL, and serum albumin levels ≥ 3.5 g/dL.
CONCLUSION: Adherence to guidelines significantly influences survival in South Korean stage B HCC patients. Curative treatments outperform TACE, but liver resection should be selected with caution due to disease heterogeneity
Variability study of Si nanowire FETs with different junction gradients
No full textRandom dopant fluctuation effects of gate-all-around Si nanowire field-effect transistors (FETs) are investigated in terms of different diameters and junction gradients. The nanowire FETs with smaller diameters or shorter junction gradients increase relative variations of the drain currents and the mismatch of the drain currents between source-drain and drain-source bias change in the saturation regime. Smaller diameters decreased current drivability critically compared to standard deviations of the drain currents, thus inducing greater relative variations of the drain currents. Shorter junction gradients form high potential barriers in the source-side lightly-doped extension regions at on-state, which determines the magnitude of the drain currents and fluctuates the drain currents greatly under thermionic-emission mechanism. On the other hand, longer junction gradients affect lateral field to fluctuate the drain currents greatly. These physical phenomena coincide with correlations of the variations between drain currents and electrical parameters such as threshold voltages and parasitic resistances. The nanowire FETs with relatively-larger diameters and longer junction gradients without degrading short channel characteristics are suggested to minimize the relative variations and the mismatch of the drain currents. (C) 2016 Author(s). All article content, except where otherwise noted, is licensed under a Creative Commons Attribution (CC BY) license (http://creativecommons.org/licenses/by/4.0/).1163Ysciescopu
Phenazine-1-carboxylic acid (PCA) produced by Paraburkholderia phenazinium CK-PC1 aids postgermination growth of Xyris complanata seedlings with germination induced by Penicillium rolfsii Y-1
No full textSymbiosis of Penicillium rolfsii Y-1 is essential for the seed germination of Hawaii yellow-eyed grass (Xyris complanata). However, the local soil where the plants grow naturally often suppresses the radicle growth of the seedlings. This radicle growth was drastically restored by coinoculation of Paraburkholderia phenazinium isolate CK-PC1, which is a rhizobacterium of X. complanata. It was found that the isolate CK-PC1 produced phenazine-1-carboxylic acid (PCA, 1) as a major metabolite. The biological effects of PCA (1) were investigated using the seeds of X. complanata and Mung bean (Vigna radiata) and it was uncovered that the symbiosis of the isolate CK-PC1was essential for the postgermination growth of X. complanata and the metabolite PCA (1) might partially contribute to promote the growth of the plants
Examination of T8-T5 electronic ballast adaptor
No full textAuthor name used in this publication: K. W. E. ChengRefereed conference paper2006-2007 > Academic research: refereed > Refereed conference paperVersion of RecordPublishedPublisher permissio
Association of Regular Endoscopic Screening with Interval Gastric Cancer Incidence in the National Cancer Screening Program
No full textAlthough regular endoscopic screening may help in early detection of gastric cancer, interval cancer remains a problem in the screening program. This study evaluated the association between regular endoscopic screening and interval cancer detection in the Korean National Cancer Screening Program (KNCSP). We defined three groups (regularly, irregularly, and not screened) according to the screening interval, and the trends in the interval cancer rate (ICR) between the groups were tested using the Cochran–Armitage test. The influence of regular endoscopic screening on the risk of interval cancer was evaluated using multivariable logistic regression. Among the 11,642,410 participants who underwent endoscopy, the overall ICR was 0.36 per 1000 negative screenings. The ICR of the not screened group (0.41) was the highest among the three groups and the risk of interval cancer in this group was 1.68 times higher (p < 0.001) than that in the regularly screened group. Women in their 40s who had regular screening with no history of intestinal metaplasia and gastric polyps would have the lowest probability of having interval cancer (0.005%). Regular participation in endoscopic screening programs for reducing the risk of interval cancer may help to improve the quality of screening programs
Association of Intensive Endoscopic Screening Burden with Gastric Cancer Detection
No full textImportance: The rapidly increasing number of gastric cancer examinations performed over a short period might influence screening performance. Accessing the association between calendar month and gastric cancer detection rates might improve policy and guide institutional support. Objective: To evaluate the association between the increased number of examinations over a certain period and gastric cancer detection rates among a large population included in the Korean National Cancer Screening Program (KNCSP). Design, Setting, and Participants: This retrospective, population-based cohort study used data from the KNCSP comprising 26765665 men and women aged 40 years or older who participated in the screening program between January 1, 2013, and December 31, 2016. Data were analyzed from November 1, 2019, to March 31, 2020. Exposures: Gastric cancer screening with endoscopy. Main Outcomes and Measures: The primary outcome was monthly gastric cancer detection rates in the KNCSP. A negative binomial regression model was used to evaluate the association between the screening month and detection rates. Results: In total, 21535222 individuals underwent endoscopy (mean [SD] age, 55.61 [10.61] years; 11761709 women [54.62%]). The quarterly number of participants was the highest in the last quarter of the study period (2013-2014: 4094951 [41.39%], 2015-2016: 4911629 [42.19%]); this proportion was 2.48 to 2.84 times greater than that of the first quarter. Cancer detection rates were the lowest in December (2013-2014: 0.22; 95% CI, 0.22-0.23; 2015-2016: 0.21; 95% CI, 0.21-0.22); this was approximately a 40.0% to 45.0% reduction compared with the rates in January. The age group was the significant factor for monthly detection rates. After adjustment for the age group and taking account of the number of screenings, the estimated coefficient range for the screening month was negative and the detection rate in December was significantly different than in January for both the consequent cycles (2013-2014: -0.05 to -0.18; P <.001; and 2015-2016: -0.06 to -0.19; P <.001). In the multivariable logistic model, the association of calendar month with detected cancer remained after adjusting for other confounding factors (December, 2013-2014: odds ratio, 0.82; 95% CI, 0.76-0.87; P <.001; 2015-2016: odds ratio, 0.83; 95% CI, 0.79-0.89; P <.001). Conclusions and Relevance: The findings of this cohort study suggest that the workload of endoscopists increased with the increasing number of examinations toward the end of the year, as demonstrated by the decreased cancer detection rates. These findings may help to improve gastric cancer detection rates of screening programs by controlling the monthly screening number and policy modifications
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