175 research outputs found

    Application of optimal control to the epidemiology of malaria

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    Malaria is a deadly disease transmitted to humans through the bite of infected female mosquitoes. In this paper a deterministic system of differential equations is presented and studied for the transmission of malaria. Then optimal control theory is applied to investigate optimal strategies for controlling the spread of malaria disease using treatment, insecticide treated bed nets and spray of mosquito insecticide as the system control variables. The possible impact of using combinations of the three controls either one at a time or two at a time on the spread of the disease is also examined

    Comparative Cost Analysis Between Hydraform Interlocking Brick and Sandcrete Block as Walling Materials for Low-Cost Housing Development in Nigeria

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    This study analyzed the cost of production and construction of 225mm hollow sandcrete blocks and hydraform interlocking bricks and walls to compare the findings of the results. The study was conducted in Auchi, Estako West Local Government Area of Edo State, Nigeria. The study compared the construction of two models of 225mm hollow sandcrete blocks and hydraform interlocking bricks, materials employed for wall construction for the study are; clay, cement, sand, water and mould. The result of the study indicates that unit cost of 225mm hollow sandcrete block and hydraform interlocking bricks are ₦168.57 and ₦57.85 respectively. While the cost per square metre of 225mm hollow sandcrete block wall and hydraform interlocking brick wall are ₦3,199.40 and ₦3,079.52 respectively. The study also revealed that it is more costly to apply finishes to sandcrete block wall when compared with hydraform interlocking brick wall. Sandcrete block wall requires rendering or plastering to both faces of the walls, while hyraform interlocking wall requires rendering of not more than 300mm girth to vertical external corners of the brick wall. The study, therefore, recommends the use of hydraform interlocking bricks for low-cost housing to reduce the housing deficit in Nigeria. Keywords: Sandcrete block; hydraform interlocking brick; walling; cost analysis; Auchi; DOI: 10.7176/JNSR/11-22-07 Publication date: November 30th 202

    Smart Flow Steering Agent for End-to-End Delay Improvement in Software-Defined Networks

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    لضمان الإستجابة للخطأ والإدارة الموزعة، يتم استخدام البروتوكولات الموزعة كأحد المفاهيم المعمارية الرئيسية التي تتضمنها شبكة الإنترنت. ومع ذلك، يمكن التغلب على عدم الكفاءة وعدم الاستقرار والقصور بمساعدة بنية الشبكات الجديدة التي تسمى الشبكات المعرفة بالبرمجيات SDN. الخاصية الرئيسية لهذه المعمارية هي فصل مستوى التحكم عن مستوى البيانات. إن تقليل التصادم سيؤدي إلى تحسين سرعة الإستجابة وزيادة البيانات المرسلة بصورة صحيحة، لهذا السبب يجب أن يكون هناك توزيع متجانس للحمل المروري عبر مسارات الشبكة المختلفة. تقدم هذه الورقة البحثية أداة توجيه ذكية SFSA لتوجيه تدفق البيانات بناءاً على ظروف الشبكة الحالية. لتحسين الإنتاجية وتقليل زمن الوصول، فإن الخوارزمية المقترحة SFSA تقوم بتوزيع حركة مرور البيانات داخل الشبكة على مسارات مناسبة ، بالإضافة إلى الإشراف على الإرتباطات التشعبية وحمل مسارات نقل البيانات. تم استخدام سيناريو خوارزمية توجيه شجرة الامتداد الدنياMST وأخرى مع خوارزمية التوجيه المعروفة بفتح أقصر مسار أولاً OSPF لتقييم جودة الخوارمية المقترحة SFSA . على سبيل المقارنة ، بالنسبة لخوارزميات التوجيه المذكروة آنفاً ، فقد حققت استراتيجيةSFSA المقترحة انخفاضاً بنسبة 2٪ في معدل ضياع حزم البيانات PDR ، وبنسبة تتراوح بين 15-45٪ في سرعة إستلام البيانات من المصدر إلى الالوجهة النهائية لحزمة البيانات وكذلك انخفاض بنسبة 23 ٪ في زمن رحلة ذهاب وعودة RTT . تم استخدام محاكي Mininet ووحدة التحكم POX لإجراء المحاكاة. ميزة أخرى من SFSA على MST و OSPF هي أن وقت التنفيذ والاسترداد لا يحمل تقلبات. يتقوم أداة التوجيه الذكية المقترحة في هذه الورقة البحثية من فتح أفقاً جديداً لنشر أدوات ذكية جديدة في شبكة SDN تعزز قابلية برمجة الشبكات وإدارتها .To ensure fault tolerance and distributed management, distributed protocols are employed as one of the major architectural concepts underlying the Internet. However, inefficiency, instability and fragility could be potentially overcome with the help of the novel networking architecture called software-defined networking (SDN). The main property of this architecture is the separation of the control and data planes. To reduce congestion and thus improve latency and throughput, there must be homogeneous distribution of the traffic load over the different network paths. This paper presents a smart flow steering agent (SFSA) for data flow routing based on current network conditions. To enhance throughput and minimize latency, the SFSA distributes network traffic to suitable paths, in addition to supervising link and path loads. A scenario with a minimum spanning tree (MST) routing algorithm and another with open shortest path first (OSPF) routing algorithms were employed to assess the SFSA. By comparison, to these two routing algorithms, the suggested SFSA strategy determined a reduction of 2% in packets dropped ratio (PDR), a reduction of 15-45% in end-to-end delay according to the traffic produced, as well as a reduction of 23% in round trip time (RTT). The Mininet emulator and POX controller were employed to conduct the simulation. Another advantage of the SFSA over the MST and OSPF is that its implementation and recovery time do not exhibit fluctuations. The smart flow steering agent will open a new horizon for deploying new smart agents in SDN that enhance network programmability and management

    Model of fire safety management for the assessment of an office building in FCT Abuja Nigeria

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    Fire safety management is essential in the aspects of achieving absolute fire safety standards in a building. Various Fire safety assessment methodologies and fire risk evaluation process has been developed over time, in spites of this, the fire risk keeps increasing, which implied that, there is a poor fire safety management. This study proposes a model of fire safety management for the fire risk assessment of an office building in Nigeria. The ten components of fire safety management were selected from the literature review, which was later structured to form criteria. The relative importance index was used to rank the level of compliance of fire safety management base on their influence. The questionnaires were the distribution to 30 fire safety practitioners and experts with substantial experience and knowledge in fire safety management. The data were analyzed using the relative importance index analytical approach. The evaluation model was suggested base on fire safety practitioners and experts’ perceptions. The inspection/observation of an office building was conducted in Nigeria in order to validate the model. The findings revealed that there is higher fire risk due to non- compliance with the standard fire safety management

    Adequate fire safety training for the occupants knowledge and awareness of fire safety

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    Achievement of fire safety objectives in buildings for the safety of lives, property conservation and business continuity is a collective responsibility of all the stakeholder, and its depends on the level of fire safety knowledge and awareness of the concern stakeholders. Therefore, this research was conducted to determine the fire safety training needs of fire safety practitioners and building managers for adequate fire safety knowledge and awareness of the building occupants in Nigeria. The research adopted questionnaires survey research design. The research population for the study comprises of 349 building manager and fire safety practitioners from six (6) north-central states of Nigeria. A research questionnaires was design for the study, the questionnaires was distributed to collect the data from the participants and was validated by experience fire safety experts; the Cronbach alpha reliability approach was used to identified the internal consistency of the questionnaires items at 0.933. the collected data were analyzed through CFA using SPSS and AMOS software, after the analysis, the data from the participants were adjudge appropriate for inclusion into the confirmatory factor analysis. The CFA was carried out and finding from the analysis is in agreement with one-factor model of fire safety training program for the enhancement of the occupant’s fire safety knowledge and awareness. The research found that fire safety practitioners and building manager requires the components for effective fire safety training. Therefore, it was suggested that the stakeholders should prioritize adequate fire safety training of the occupants and public in the fire safety for boosting their knowledge and awareness of fire safety

    SELECTED WELFARE PARAMETERS OF BROILER CHICKENS ON DIFFERENT FEED QUANTITY AND TIME

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    This study was conducted to determine welfare of broiler chickens fed ad libitum and restricted feed during early (08.00hour) and late (16:00hour) of the day. One hundred and eighty (21d old) broiler chickens were randomly allocated to 4 treatments in a 2x2 factorial arrangement comprising of ad libitum and restricted feeding (75% of ad libitum) quantity at 8 and 16 hours feeding time in three replicates. Data were collected on leg problem, dust bathing, body temperature, mortality and haematology. Result revealed that neither feed quantity nor time had significant (P>0.05) effect on leg problem, dust bathing and mortality of broiler chickens. Broiler chickens under ad lib feed quantity and 16:00hours feeding time had (P<0.05) highest body temperature (40.93oC) while those under ad libitum morning (08:00hours) recorded the least (40.75°C). Pack Cell Volume had similar (P>0.05) increase from 26.75% at the beginning (21d) to 31.25 (%) at 56d with broiler chickens under restricted feeding and fed at 16:00hours feeding time. Basophil count reduced from a range of 0.5-2% (P<0.05) to 1% (P>0.05) with restricted feeding. Also eosinophil reduced from 2-4% (P<0.05) range to 0-2.5% (P>0.05) with restricted feeding while birds under ad lib increased from 0-1% (P<0.05) at 21d to 2.75% (P>0.05) at 56d. Better welfare (good body temperature) of broiler chicken could be achieved with early feeding time irrespective of quantity. However, restricted feeding could be explored in broiler production where reduced basophil, eosinophil and stress are vital for enhanced welfare and performance.   &nbsp
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