465 research outputs found

    Optimal control of a large dam

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    A large dam model is an object of study of this paper. The parameters LlowerL^{lower} and LupperL^{upper} are its lower and upper levels, L=LupperLlowerL=L^{upper}-L^{lower} is large, and if a current level of water is between these bounds, then the dam is assumed to be in normal state. Passage one or other bound leads to damage. Let J1J_1 (J2)(J_2) denote the damage cost of crossing the lower (upper) level. It is assumed that input stream of water is described by a Poisson process, while the output stream is state-dependent (the exact formulation of the problem is given in the paper). Let LtL_t denote the dam level at time tt, and let p1=limtP{Lt=Llower}p_1=\lim_{t\to\infty}\mathbf{P}\{L_t= L^{lower}\}, p2=limtP{Lt>Lupper}p_2=\lim_{t\to\infty}\mathbf{P}\{L_t> L^{upper}\} exist. The long-run average cost J=p1J1+p2J2J=p_1J_1+p_2J_2 is a performance measure. The aim of the paper is to choose the parameter of output stream (exactly specified in the paper) minimizing JJ.Comment: To appear in "Journal of Applied Probability" 44 (2007), No.

    Design of Adiabatic MTJ-CMOS Hybrid Circuits

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    Low-power designs are a necessity with the increasing demand of portable devices which are battery operated. In many of such devices the operational speed is not as important as battery life. Logic-in-memory structures using nano-devices and adiabatic designs are two methods to reduce the static and dynamic power consumption respectively. Magnetic tunnel junction (MTJ) is an emerging technology which has many advantages when used in logic-in-memory structures in conjunction with CMOS. In this paper, we introduce a novel adiabatic hybrid MTJ/CMOS structure which is used to design AND/NAND, XOR/XNOR and 1-bit full adder circuits. We simulate the designs using HSPICE with 32nm CMOS technology and compared it with a non-adiabatic hybrid MTJ/CMOS circuits. The proposed adiabatic MTJ/CMOS full adder design has more than 7 times lower power consumtion compared to the previous MTJ/CMOS full adder

    Behavior of hybrid high-strength fiber reinforced concrete slab-column connections under the effect of high temperature

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    AbstractConcrete can be modified to perform in a more ductile form by the addition of randomly distributed discrete fibers in the concrete matrix. The combined effect of the addition of two types of fibers (steel fiber and polypropylene fiber with different percentages) to concrete matrix, which is called hybrid effect is currently under investigation worldwide. The current research work presents the conducted experimental program to observe the behavior of hybrid high strength reinforced concrete slab-column connections under the effect of high temperature. For this purpose, ten slab-column connections were casted and tested. The experimental program was designed to investigate the effect of different variables such as concrete mixture, column location and temperature fighting system. All specimens were exposed to a temperature of 500°C for duration of two hours. To observe the effect of each variable, specimens were divided into four groups according to the studied parameters. The test results revealed that using hybrid high strength concrete HFHSC produced more strength in punching failure compared with high strength concrete HSC when exposed to elevated temperature. Fighting by air had higher initial crack load compared with that for without fighting and fighting by water. On the other hand, fighting by water decreased the ultimate load

    Translating Bloom’s Taxonomy Action Verb List into Arabic for Teacher Preparation Programs: Challenges/Problems and Solutions

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    This paper presents a unified Arabic version of the English action verbs mentioned in Bloom’s taxonomy (1956) that has been checked for validity and reliability by a panel of education experts. Methodologically, the Bloom’s list of action verbs was first translated into Arabic by an expert professor of translation. Then, using a mixed-method approach the Arabic list was validated by three bilingual education experts working at universities in Bahrain, Qatar, and the United Arab Emirates. As part of the process, the paper established a single Bloom’s taxonomy list of action verbs, based on the data provided by two reputable educational institutions that were cross-checked with a well-referenced textbook. A contextualized Arabic translation of the list was then produced and was subjected to rigorous checks by a panel of reviewers who were the education experts. The paper presents the challenges faced in translating the list into Arabic and the solutions we have adopted as well as the validity and reliability checks. The implication of this paper is in offering teacher preparation programs across the Arab world an Arabic Bloom’s taxonomy list that can be used by in-service and pre-service teachers. Moreover, it contributes to teacher literacy in the correct use of Bloom’s action verbs in the Arabic language

    Extracorporeal Shockwave Therapy for Painful Chronic Traumatic Heterotopic Ossification after Right Acetabulum Fracture Fixation: A Case Report and Literature Review

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    BACKGROUND: Heterotopic ossification (HO) usually occurs in trauma, such as fractures. To the best of our knowledge, there is a lack of studies about the effects of shockwave on the size of HO in the literature. AIM: The aim of this study was to describe the effects of extracorporeal shockwave therapy (ESWT) on the size of HO as well as the lower extremity functions in patients with fracture right acetabulum. CASE REPORT: A 36-year-old gentleman had a traffic accident on August 30, 2015, resulted in a fracture of the right acetabulum treated by open reduction and internal fixation on September 2, 2015. The patient has complained of severe right hip pain with limitation of daily activities, especially walking, standing, and sitting, visual analog scale about 7-8/10 with painful and restricted ROM of the right hip. Plain X-ray of the right hip revealed HO at greater trochanter with a long axis length 37.3 mm. ESWT was applied for HO. ESWT was administered 6 times each weekly for 6 weeks. At 6-month follow-up, the size of HO had become slightly smaller with the improvement of pain, and lower extremities functions. DISCUSSION: Soft tissues around HO have been regenerated from ischemia for several reasons such as ESWT stimulating angiogenesis and neurogenesis and the size of HO had become slightly smaller by radial shockwave therapy. CONCLUSION: ESWT is a novel non-invasive and safe treatment for HO. The effects of ESWT on the size of HO had become slightly smaller with the improvement of lower extremities functions
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