2,064 research outputs found

    Fuzzy logic control for camera tracking system

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    A concept utilizing fuzzy theory has been developed for a camera tracking system to provide support for proximity operations and traffic management around the Space Station Freedom. Fuzzy sets and fuzzy logic based reasoning are used in a control system which utilizes images from a camera and generates required pan and tilt commands to track and maintain a moving target in the camera's field of view. This control system can be implemented on a fuzzy chip to provide an intelligent sensor for autonomous operations. Capabilities of the control system can be expanded to include approach, handover to other sensors, caution and warning messages

    A Decade of Cholecystectomy at Kenyatta National Hospital: Demographics, Patterns and Transition to Laparoscopy

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    Background: In the early 90’s all cholecystectomies at the Kenyatta National Hospital were open cholecystectomies. Currently only third undergo the open operation. We conducted a study to analyze the age and sex, mode of presentation, investigations done and operation performed, in view of the changing mode of treatment from open to laparoscopic cholecystectomy (LC). Methods: A Retrospective descriptive study over 10 years from 2001 to 2010. Results: 207 patient files could be traced of whom 80% were females and 40% were under 40years. Almost all patients presented with RUQ pain with about half having a positive Murphy’s sign. Abdominal Ultrasound (USs) was available to most patients and with good reporting. However pertinent laboratory investigations especially liver function tests were not done in over half the patients. LC was offered to about 67% of the patients with a conversion rate of 5%. Conclusion: Kenyatta National Hospital must strive to increase laparoscopic procedures. There is also need to improve the pre-operative laboratory investigations in patients with gallstones.Key Words: Cholecystectomy, Transition, Laparoscopy, Developing countr

    Impairments in motor coordination without major changes in cerebellar plasticity in the Tc1 mouse model of Down syndrome

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    Down syndrome (DS) is a genetic disorder arising from the presence of a third copy of human chromosome 21 (Hsa21). Recently, O’Doherty et al. [An aneuploid mouse strain carrying human chromosome 21 with Down syndrome phenotypes. Science 309 (2005) 2033–2037] generated a trans-species aneuploid mouse line (Tc1) that carries an almost complete Hsa21. The Tc1 mouse is the most complete animal model for DS currently available. Tc1 mice show many features that relate to human DS, including alterations in memory, synaptic plasticity, cerebellar neuronal number, heart development and mandible size. Because motor deficits are one of the most frequently occurring features of DS, we have undertaken a detailed analysis of motor behaviour in cerebellum-dependent learning tasks that require high motor coordination and balance. In addition, basic electrophysiological properties of cerebellar circuitry and synaptic plasticity have been investigated. Our results reveal that, compared with controls, Tc1 mice exhibit a higher spontaneous locomotor activity, a reduced ability to habituate to their environments, a different gait and major deficits on several measures of motor coordination and balance in the rota rod and static rod tests. Moreover, cerebellar long-term depression is essentially normal in Tc1 mice, with only a slight difference in time course. Our observations provide further evidence that support the validity of the Tc1 mouse as a model for DS, which will help us to provide insights into the causal factors responsible for motor deficits observed in persons with DS

    Modified discrete Fourier transform algorithm for protection of shunt compensated distribution line

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    Introduction. The response time of the relay plays vital role when fault occurs on the line. Various algorithms are adopted to increase the sampling rate of the relay which, in turn, improves the response time. Methods. Discrete Fourier transform and modified discrete Fourier transform are the two algorithms used to calculate the fundamental frequency phasor of the signal required by the relay to initiate trip command. It is known that discrete Fourier transform takes four to five cycles to produce the fundamental frequency phasor but it fails to deal with the decaying DC component. On the other hand, modified discrete Fourier transform improves the response time by removing the decaying DC component along with the other harmonics in just one cycle and a few samples. The aim of this paper is to cover discrete Fourier transform and modified discrete Fourier transform algorithms to analyze the performance of the three overcurrent and one earth fault relaying scheme for different types of faults occurring in the distribution system. Methodology. The concept of three overcurrent and one earth fault scheme is also explained in this paper for protection of shunt-compensated distribution system. The scheme is designed for variable power factor. MATLAB/Simulink is used as the software tool to validate the results obtained for various types of faults occurring in the system. The results are represented graphically to illustrate the time of response of the protection scheme when shunt compensators are connected at the receiving end of distribution network.Вступ. Час спрацювання реле відіграє життєво важливу роль при виникненні несправності на лінії. Для збільшення частоти дискретизації реле застосовуються різні алгоритми, що, своєю чергою, покращує час спрацювання. Методи. Дискретне перетворення Фур’є та модифіковане дискретне перетворення Фур’є – це два алгоритми, які використовуються для розрахунку вектора основної частоти сигналу, необхідного для реле подачі команди на відключення. Відомо, що для отримання вектора основної частоти дискретного перетворення Фур’є потрібно від чотирьох до п'яти циклів, але воно не справляється з постійною складовою струму, що згасає. З іншого боку, модифіковане дискретне перетворення Фур’є покращує час спрацювання, видаляючи постійну складову струму, що згасає, разом з іншими гармоніками всього за один цикл і кілька вибірок. Мета цієї статті полягає в тому, щоб охопити алгоритми дискретного перетворення Фур’є та модифікованого дискретного перетворення Фур’є для аналізу характеристик трьох схем реле максимального струму та однієї схеми захисту від замикань на землю для різних типів несправностей, що виникають у розподільчій системі. Методологія. У статті  пояснюється також концепція трьох схем перевантаження по струму і однієї схеми замикання на землю для захисту розподільчої системи з паралельною компенсацією. Схема розрахована на змінний коефіцієнт потужності. MATLAB/Simulink використовується як програмний інструмент для перевірки результатів, отриманих для різних типів відмов, що виникають у системі. Результати представлені графічно, щоб проілюструвати час спрацьовування схеми захисту, коли шунтуючі компенсатори підключені на приймальному кінці розподільної мережі

    Peranan dan Strategi Pengembangan Sektor Perkebunan terhadap Pembangunan Wilayah Kabupaten Malinau

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    Kabupaten Malinau memiliki potensi yang sangat besar untuk pengembangan komoditas sektor perkebunan. Penelitian ini bertujuan untuk memetakan wilayah basis komoditas perkebunan, mengetahui kontribusi perkebunan terhadap PDRB Kabupaten Malinau, mengetahui trend perkembangan komoditas perkebunan, serta menyusun alternatif strategi pengembangan sektor perkebunan. Alat analisis data meliputi analisis Location Quotient, analisis kontribusi, analisis Trend, dan analisis SWOT. Hasil penelitian menunjukkan bahwa wilayah basis luas lahan kakao terdapat di empat kecamatan, karet basis di empat kecamatan, kelapa basis di enam kecamatan, kopi basis di tujuh kecamatan, lada basis di tiga kecamatan, sawit basis di tiga kecamatan, dan teh basis di tiga kecamatan. Wilayah basis produksi kakao terdapat di empat kecamatan, kelapa basis di enam kecamatan, kopi basis di lima kecamatan, lada basis di tiga kecamatan. Sektor perkebunan memiliki kontribusi yang rendah terhadap PDRB Kabupaten Malinau. Trend luas lahan komoditas kopi, kakao, karet, sawit, dan teh meningkat, komoditas kelapa dan lada menurun. Trend produksi komoditas kopi dan kakao meningkat, komoditas kelapa dan lada menurun. Strategi yang direkomendasikan adalah memanfaatkan kekuatan yang ada untuk meraih peluang yang ada

    Performance of screening for aneuploidies by cell-free DNA analysis of maternal blood in twin pregnancies

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    Objectives To report clinical implementation of cell‐free DNA (cfDNA) analysis of maternal blood in screening for trisomies 21, 18 and 13 in twin pregnancies and examine variables that could influence the failure rate of the test. Methods cfDNA testing was performed in 515 twin pregnancies at 10–28 weeks' gestation. The failure rate of the test to provide results was compared with that in 1847 singleton pregnancies, and logistic regression analysis was used to determine which factors among maternal and pregnancy characteristics were significant predictors of test failure. Results Failure rate of the cfDNA test at first sampling was 1.7% in singletons and 5.6% in twins. Of those with a test result, the median fetal fraction in twins was 8.7% (range, 4.1–30.0%), which was lower than that in singletons (11.7% (range, 4.0–38.9%)). Multivariable regression analysis demonstrated that twin pregnancy, higher maternal weight and conception by in‐vitro fertilization provided significant independent prediction of test failure. Follow‐up was available in 351 (68.2%) of the twin pregnancies and comprised 334 with euploid fetuses, 12 discordant for trisomy 21 and five discordant for trisomy 18. In all 323 euploid cases with a result, the risk score for each trisomy was < 1:10 000. In 11 of the 12 cases with trisomy 21 and in the five with trisomy 18, the cfDNA test gave a high‐risk result, but in one case of trisomy 21, the score was < 1:10 000. Conclusion In twin pregnancies screening by cfDNA testing is feasible, but the failure rate is higher and detection rate may be lower than in singletons

    Scoping review exploring the impact of digital systems on processes and outcomes in the care management of acute kidney injury and progress towards establishing learning healthcare systems

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    Objectives: Digital systems have long been used to improve the quality and safety of care when managing acute kidney injury (AKI). The availability of digitised clinical data can also turn organisations and their networks into learning healthcare systems (LHSs) if used across all levels of health and care. This review explores the impact of digital systems i.e. on patients with AKI care, to gauge progress towards establishing LHSs and to identify existing gaps in the research. / Methods: Embase, PubMed, MEDLINE, Cochrane, Scopus and Web of Science databases were searched. Studies of real-time or near real-time digital AKI management systems which reported process and outcome measures were included. / Results: Thematic analysis of 43 studies showed that most interventions used real-time serum creatinine levels to trigger responses to enable risk prediction, early recognition of AKI or harm prevention by individual clinicians (micro level) or specialist teams (meso level). Interventions at system (macro level) were rare. There was limited evidence of change in outcomes. / Discussion: While the benefits of real-time digital clinical data at micro level for AKI management have been evident for some time, their application at meso and macro levels is emergent therefore limiting progress towards establishing LHSs. Lack of progress is due to digital maturity, system design, human factors and policy levers. / Conclusion: Future approaches need to harness the potential of interoperability, data analytical advances and include multiple stakeholder perspectives to develop effective digital LHSs in order to gain benefits across the system
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