3,769 research outputs found
SCHEDULING IN MULTIBEAM SATELLITES WITH INTERFERING ZONES
No full textThe traffic scheduling problem is studied in a satellite-switched time-division multiple-access system with interfering beams. A two-step approach is investigated, the first step being the assignment of orthogonal polarization to reduce the interference, and the second step being the scheduling of traffic, taking into account the ′′resultant′′ interference. The first step can be solved in polynomial time in most cases, while the second step is proved to be NP-complete, even for very simple interference patterns. Several suboptimal algorithms for this second step are suggested
INCREMENTAL TIME-SLOT ASSIGNMENT IN SS TDMA SATELLITE SYSTEMS
No full textIn this paper we investigate the problem of incremental time-slot assignment for a satellite switched time division multiple access (SS/TDMA) satellite system in an heterogeneous traffic environment. The traffic in this environment can be categorized into two types: a rapidly changing type composed of packet-switched data traffic, and a relatively static type composed of circuit-switched voice traffic. From the time-slot assignment viewpoint, the problem is to construct an "efficient" TDMA frame that permits the static voice traffice to be transmitted and then, on a frame-by-frame basis to attempt to insert the data packets into the slots that are unused by the voice traffic. We prove that the problem is NP-complete, even for very simple traffic configurations. Several suboptimal fast heuristic algorithms are presented and empirically compared by experiments on randomly generated traffic patterns. The experiments reveal that, on the average, the algorithms give close to the optimal performance
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
Abstract P5-07-09: Identification of miRNA biomarkers for early diagnosis of basal-like breast cancer
No full textAbstract
The routine screening for breast cancer relies primarily on imaging techniques such as mammography and ultrasonography, but it is often not sensitive enough for early detection and requires complementary approaches. Recent studies suggest that microRNAs (miRNAs) could be used as biomarkers for breast cancer due to its relative stability in archived formalin-fixed tissues as well as in bodily fluids. However, the identity of unique miRNAs that could discriminate proliferative and malignant states of the disease has remained elusive. Since TGFβ-induced epithelial-mesenchymal transition (EMT) represents a critical step during tumor progression and intravasation, studying the cancer cell at the mesenchymal state and its precursor could help to identify these critical diagnostic biomarkers. To identify novel biomarkers for early detection, we performed miRNA gene expression profiling of an established basal-like breast cancer (BLBC) model system with and without disruption of TGFβ signaling. We have identified a panel of miRNAs, including miR-210-3p, that are highly expressed in the motile, mesenchymal stage, which could potentially be used as markers in liquid biopsies for early detection of invasive BLBC. Conversely, we also found some miRNAs, including miR-200c and miR-4417, highly expressed in the noninvasive, epithelial stage. Transient overexpression of miR-4417 in mesenchymal BLBC cells was able to suppress migration and mammosphere formation in vitro, suggesting that it could block progression of BLBC, a disease highly prevalent in young African-American women and lacks targeted therapy.
Citation Format: Wong CK, Thiagalingam S. Identification of miRNA biomarkers for early diagnosis of basal-like breast cancer [abstract]. In: Proceedings of the 2017 San Antonio Breast Cancer Symposium; 2017 Dec 5-9; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2018;78(4 Suppl):Abstract nr P5-07-09.</jats:p
Prevalence of GERD in Southeast Asian countries
No full textThe reported population prevalence of GERD in eastern Asia ranged from 2.5% to 6.7% for at least weekly symptoms of heartburn and/or acid regurgitation. Typical GERD symptoms are consistently less common among the general populations of Asia than those in the West which have a prevalence of around 20% for weekly refl ux symptoms. No reliable data are available on the prevalence of esophagitis in the general population. In case studies the prevalence of refl ux esophagitis ranged from 3.4% to 16.3%. A large study in Hong Kong in patients undergoing routine or emergency upper endoscopy (n=16,606) showed that 3.8% of the patients had esophagitis demonstrated by endosocpy and the majority (94%) had Los Angeles Classifi cation Grade A or B esophagitis and only 14 patients (0.08%) had esophageal stricture. Rosaida et al. have shown that in a prospective study, 65.5% of their patients had NERD. In another study from Hong Kong, it was found that 46.7% (215 of 460 subjects) of patients with typical refl ux symptoms had no endoscopic evidence of esophagitis. In a study from Singapore, patients with NERD were signifi cantly younger, more likely to have minor psychiatric morbidity and were less likely to respond to proton pump inhibitors (PPI) when compared with patients with erosive esophagitis. In summary, the prevalence of refl ux esophagitis appears to be lower in Asian population and the disease spectrum is milder in Asians. Prevalence of Barrett's varies between different countries. In a study of multi-ethnic Malaysian population, Barrett's esophagus was reported in 1.6% of those undergoing elective endoscopy for upper abdominal or refl ux complaints. A much lower prevalence was found in southern Chinese patients undergoing upper endoscopy, of whom only 0.06% were found (n=22,628). More data are required to determine the true prevalence of Barrett's esophagus in Asians. The prevalence of GERD in Asia may be increasing. In a 1999 re-survey of a cohort of community residents in Singapore who were interviewed in an earlier study in 1994, Lim et al. reported a more than 6 fold increase in the reporting of refl ux symptoms, from a prevalence of 1.6% to a prevalence of 9.9%. In a 1-year follow up study in Hong Kong, Wong et al. reported an increase in the annual, monthly and weekly prevalence of GERD from 29.8%, 8.9% and 2.5% to 34.1%, 10.1% and 2.7%, respectively. REFERENCES: 1. Wong WM, Lai KC, Lam KF, Hui WM, Hu WH, Lam CL, Xia HH, Huang JQ, Chan CK, Lam SK, Wong BC. Prevalence, clinical spectrum and health care utilization of gastro-oesophageal refl ux disease in a Chinese population: a population-based study. Aliment Pharmacol Ther 2003;18:595-604. 2. Wong WM, Lai KC, Lam KF, Hui WM, Huang JQ, Xia HH, Hu WH, Lam CL, Chan CK, Lam SK, Wong BC. Onset and disappearance of refl ux symptoms in a Chinese population: a 1-year follow-up study. Aliment Pharmacol Ther 2004;20:803-12. 3. Wong BC, Kinoshita Y. Systematic review on epidemiology of gastroesophageal refl ux disease in Asia. Clin Gastroenterol Hepatol 2006;4:398-407. 4. Wong WM, Lam SK, Hui WM, Lai KC, Chan CK, Hu WH, Xia HH, Hui CK, Yuen MF, Chan AO, Wong BC. Long-term prospective follow-up of endoscopic oesophagitis in southern Chinese--prevalence and spectrum of the disease. Aliment Pharmacol Ther 2002;16:2037-42.link_to_subscribed_fulltex
Highly 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
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Hong Kong: workfare in the world's freest economy
No full textWorkfare was introduced in many countries to suppress welfare dependency and reduce social security expenditures. However, workfare was launched in Hong Kong when there was only a relatively small social security budget and its citizens still strongly adhered to the ideologies of self-reliance. It was found that workfare has performed several functions in Hong Kong. Firstly, it has forced unemployed claimants to give up benefits so that Hong Kong's social security expenditures can be saved. Secondly, workfare had combined with Hong Kong's semi-democratic polity so that extremely stigmatising welfare measures were implemented. Thirdly, it has pushed poor citizens to the labour market without having any protection over wages and working hours. Thus, the combination of workfare and a semi-democratic polity has successfully suppressed Hong Kong's welfare demands and strengthened its self-help spirit. As a result, Hong Kong's minimal social security scheme and its low tax policy have been maintained
sj-pdf-1-pmj-10.1177_02692163211049309 – Supplemental material for Pain assessment tools in paediatric palliative care: A systematic review of psychometric properties and recommendations for clinical practice
No full textSupplemental material, sj-pdf-1-pmj-10.1177_02692163211049309 for Pain assessment tools in paediatric palliative care: A systematic review of psychometric properties and recommendations for clinical practice by Adrienne YL Chan, Mengqin Ge, Emily Harrop, Margaret Johnson, Kate Oulton, Simon S Skene, Ian CK Wong, Liz Jamieson, Richard F Howard and Christina Liossi in Palliative Medicine</p
sj-pdf-2-pmj-10.1177_02692163211049309 – Supplemental material for Pain assessment tools in paediatric palliative care: A systematic review of psychometric properties and recommendations for clinical practice
No full textSupplemental material, sj-pdf-2-pmj-10.1177_02692163211049309 for Pain assessment tools in paediatric palliative care: A systematic review of psychometric properties and recommendations for clinical practice by Adrienne YL Chan, Mengqin Ge, Emily Harrop, Margaret Johnson, Kate Oulton, Simon S Skene, Ian CK Wong, Liz Jamieson, Richard F Howard and Christina Liossi in Palliative Medicine</p
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