403 research outputs found
Improving search order for reachability testing in timed automata
Standard algorithms for reachability analysis of timed automata are sensitive
to the order in which the transitions of the automata are taken. To tackle this
problem, we propose a ranking system and a waiting strategy. This paper
discusses the reason why the search order matters and shows how a ranking
system and a waiting strategy can be integrated into the standard reachability
algorithm to alleviate and prevent the problem respectively. Experiments show
that the combination of the two approaches gives optimal search order on
standard benchmarks except for one example. This suggests that it should be
used instead of the standard BFS algorithm for reachability analysis of timed
automata
Assessing a chemosterilant for fertility control of rats
Fertility control of rodents could be used as an additional approach for the sustainable management of pest populations in agricultural production systems. One potential technique is the use of chemosterilants which induce long-term infertility in female animals. The aim of my research was to assess the effects of an industrial chemical, 4-vinylcyclohexene diepoxide (VCD), on reproduction of female and male laboratory rats (Rattus norvegicus). In addition, the uptake of bait types and basic formulations with potential to deliver a fertility control agent to the ricefield rat, Rattus argentiventer, a target species for fertility control in Southeast Asia, was undertaken.
In female rats, the effects on ovarian follicle populations were assessed after a period of oral treatment (500 mg VCD/kg/day for 10 days), which was then repeated either once or twice at 14 and 21 day intervals. The effect of three periods of VCD treatment on fertility was examined by mating with fertile, untreated males for 4 breeding cycles. In male rats, the effects of a single 5-day period of oral administration (500 mg VCD/kg/day) on reproductive tissues of juvenile and adult rats were assessed at different times after treatment (days 16 to 90). The effect of VCD treatment on the fertility of adult males was determined by mating with fertile, untreated females for 5 breeding cycles. In the bait-uptake study, laboratory evaluations of bait acceptance by ricefield rats were conducted using different physical forms of bait, vegetable oils, food additives and types of cereal. Based on these laboratory results, the most accepted bait formula plus Rhodamine B (RB) as a bait marker was used under field enclosure conditions to determine the proportion of animals consuming bait and the rate of bait consumption per individual.
In females, oral administration of VCD (500 mg/kg) for all treatment schemes induced significant depletion of primordial and primary follicles in the ovaries. Three periods of VCD treatment significantly enhanced ovarian follicle depletion and induced delayed but irreversible infertility. In male rats, a single oral VCD treatment for 15 days did not induce any effects on either reproductive tissues or fertility suggesting an absence of effect on the reproductive status of male rats.
Under laboratory conditions, bait in kibble form, containing cereal-base (1O% broken rice, 30% wheat and 30% rice flours), 5% coconut oil, 20% intralipid (a fatty emulsion), and 5% sugar was shown to be most preferred by ricefield rats. Under field enclosure conditions, this bait formula was highly accepted with approximately 90% of ricefield rats consuming bait, and at a high rate per individual (approximately 9.5% body weight).
This research has demonstrated that VCD has potential as a candidate for fertility control of rats, and that a cereal-based bait formula derived in this study could potentially be used as a carrier for oral delivery of fertility control agents in ricefield rats. In the future, fertility control could be used as an additional integrated tool for improved management of pest rodents and thus could significantly contribute to food security and poverty alleviation programs in developing countries
A Prototype of Automated Chayote Peeling Machine
Fruit peeling seems a simple performance, but it is the consist of many elements such as the peeler, the way we grasp and move the blade and cutting speed, etc. - all these factors play a role, and interact with each other. This paper describes the prototype of a chayote peeling machine. The machine has been designed with a simple and low-cost approach. To improve chayote peeling rate and ensure pulp quality, a proposed structure was designed, manufactured and tested in laboratory. The experimental results are examined to demonstrate the efficiency of the peeling machine. It proves that the proposed machine could be widely applied in the fruit peeling technology
THE EFL 8TH GRADERSâ ATTITUDES TOWARDS THE USE OF COMPETENCY-BASED INSTRUCTION IN LISTENING COMPREHENSION AT A SECONDARY SCHOOL IN KIEN GIANG, VIETNAM
Listening skill is a vital component of language acquisition on the grounds that it can foster the improvement of other language skills. Therefore, enhancing studentsâ listening is constantly gaining the prominent attention of most English teachers at secondary schools. Besides, applying competency-based instruction into teaching listening is a novel method that helps teachers attain studentsâ attitudes, affecting their listening comprehension. Therefore, this current study aimed to examine studentsâ attitudes toward using competency-based instruction in listening for a main idea and specific information. The study employed a qualitative approach to determine 45 8th gradersâ attitudes at a secondary school in Kien Giang province. The studentsâ diaries were the critical data collection. The studyâs findings showed that their views affected their listening skills. Most of them had positive attitudes toward the utilization of competency-based instruction in listening comprehension. Article visualizations
Interface de contrĂŽle automatisĂ© dâun systĂšme de camĂ©ras robotisĂ©es pour la tĂ©lĂ©traumatologie
De nos jours, la tĂ©lĂ©mĂ©decine est appliquĂ©e universellement dans plusieurs domaines de la mĂ©decine comme la radiologie, la pathologie et la psychiatrie. Depuis 2004, le Centre hospitalier universitaire de Sherbrooke (CHUS), la FacultĂ© de mĂ©decine et des sciences de la santĂ© et la FacultĂ© de gĂ©nie de lâUniversitĂ© de Sherbrooke dĂ©veloppent un systĂšme des camĂ©ras robotisĂ©es permettant Ă un traumatologue dâinteragir Ă distance avec un mĂ©decin intervenant en salle dâurgence, dans un contexte de tĂ©lĂ©traumatologie. Ce systĂšme demande au traumatologue de contrĂŽler et de positionner les camĂ©ras tout en observant lâintervention. Afin quâil puisse se concentrer le plus possible sur lâintervention chirurgicale au lieu de sâattarder au contrĂŽle du systĂšme, une assistance de positionnement des camĂ©ras sâavĂ©rerait utile. Lâobjectif de ce projet est de concevoir une interface qui permet de positionner automatiquement les camĂ©ras robotisĂ©es tout en laissant la possibilitĂ© Ă lâopĂ©rateur de les dĂ©placer directement au besoin.
Pour ce faire, lâinterface de contrĂŽle automatisĂ© utilise des algorithmes de traitement dâimages permettant le suivi dâĂ©lĂ©ments visuels, la dĂ©tection dâobstructions dans la scĂšne observĂ©e et lâapproximation de coordonnĂ©es tridimensionnelles dâun point dans lâimage. Elle exploite deux modes de contrĂŽle : lâopĂ©rateur sĂ©lectionne une zone dâintĂ©rĂȘt directement dans la vue vidĂ©o, ou identifie une rĂ©gion dâintĂ©rĂȘt qui est suivie automatiquement par le systĂšme, et qui permet au besoin que les deux bras regardent simultanĂ©ment le dit objet de deux points de vue diffĂ©rents. Avec la dĂ©tection dâobstructions, lâinterface est en mesure de repositionner automatiquement les camĂ©ras pour garder la vue sur la zone ou la rĂ©gion dâintĂ©rĂȘt. Des tests prĂ©-cliniques menĂ©s au Laboratoire de robotique intelligente, interactive et interdisciplinaire de lâUniversitĂ© de Sherbrooke permettent dâĂ©valuer lâefficacitĂ© et la pertinence de lâinterface de contrĂŽle automatisĂ©. MalgrĂ© certaines limitations inhĂ©rentes Ă la rapiditĂ© de traitement des commandes de positionnement des camĂ©ras intĂ©grĂ©es au systĂšme, lâanalyse des rĂ©sultats suggĂšre que lâinterface de contrĂŽle automatisĂ© est conviviale et diminue la charge cognitive des opĂ©rateurs. La performance avec lâinterface de contrĂŽle automatisĂ© permettant la sĂ©lection de la zone dâintĂ©rĂȘt est plus Ă©levĂ©e que lâinterface de contrĂŽle nonautomatisĂ© (dite manuel, demandant le positionnement manuel des bras robotisĂ©s et des camĂ©ras), tandis que la performance de lâinterface de contrĂŽle automatisĂ© permettant de sĂ©lectionner et de suivre une rĂ©gion dâintĂ©rĂȘt simultanĂ©ment par les deux camĂ©ras est moins Ă©levĂ©e que lâinterface de contrĂŽle manuel
Performance of export-oriented small and medium-sized manufacturing enterprises in Viet Nam
The study recommends the formulation of policies that support the development of business linkages and networking, and which promote subcontracting arrangements between small and large enterprises or between domestic firms and foreign investment enterprises. It is also necessary to support and facilitate the direct involvement of SMMEs in exporting or indirectly through large manufacturing enterprises.Export-oriented, SME,SMME, Viet Nam
Integrated Design and Application of Inerter on Vehicle Suspension to Optimal Oscillation
èæ”Šć·„æ„性ćŠ201
Optimal control of switched capacitor banks in Vietnam distribution network using integer genetic algorithm
In distribution network, power and energy losses can be reduced by using switched capacitor banks. The capacitor banks can be switched on or off based on voltage profile or power factor or using timers. Due to variation of load, it is necessary to control the capacitor banks switching in function of load curve. This paper presents the application of an integer genetic algorithm to determine the optimal number of banks corresponding with hourly load to minimize total active power losses of distribution feeders. The problem constraints include voltage profile and heat conditions which are taken into account to the objective function by a penalty function. In this application, the structure of chromosomes is a set of numbers of the capacitor banks hourly connected to the grid. The proposed formulation is validated by a feeder. The result shows that in some cases, the active power losses at maximum compensation are greater than the ones of optimal control compensation, and the voltage reaches a higher level than the maximum voltage limit. The optimal control of switched capacitor banks can reduce power and energy losses as well as ensure maximum voltage profile within the limit
- âŠ