1,585 research outputs found

    Design and Code Optimization for Systems with Next-generation Racetrack Memories

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    With the rise of computationally expensive application domains such as machine learning, genomics, and fluids simulation, the quest for performance and energy-efficient computing has gained unprecedented momentum. The significant increase in computing and memory devices in modern systems has resulted in an unsustainable surge in energy consumption, a substantial portion of which is attributed to the memory system. The scaling of conventional memory technologies and their suitability for the next-generation system is also questionable. This has led to the emergence and rise of nonvolatile memory ( NVM ) technologies. Today, in different development stages, several NVM technologies are competing for their rapid access to the market. Racetrack memory ( RTM ) is one such nonvolatile memory technology that promises SRAM -comparable latency, reduced energy consumption, and unprecedented density compared to other technologies. However, racetrack memory ( RTM ) is sequential in nature, i.e., data in an RTM cell needs to be shifted to an access port before it can be accessed. These shift operations incur performance and energy penalties. An ideal RTM , requiring at most one shift per access, can easily outperform SRAM . However, in the worst-cast shifting scenario, RTM can be an order of magnitude slower than SRAM . This thesis presents an overview of the RTM device physics, its evolution, strengths and challenges, and its application in the memory subsystem. We develop tools that allow the programmability and modeling of RTM -based systems. For shifts minimization, we propose a set of techniques including optimal, near-optimal, and evolutionary algorithms for efficient scalar and instruction placement in RTMs . For array accesses, we explore schedule and layout transformations that eliminate the longer overhead shifts in RTMs . We present an automatic compilation framework that analyzes static control flow programs and transforms the loop traversal order and memory layout to maximize accesses to consecutive RTM locations and minimize shifts. We develop a simulation framework called RTSim that models various RTM parameters and enables accurate architectural level simulation. Finally, to demonstrate the RTM potential in non-Von-Neumann in-memory computing paradigms, we exploit its device attributes to implement logic and arithmetic operations. As a concrete use-case, we implement an entire hyperdimensional computing framework in RTM to accelerate the language recognition problem. Our evaluation shows considerable performance and energy improvements compared to conventional Von-Neumann models and state-of-the-art accelerators

    Haemodynamic response to induction, laryngoscopy and tracheal intubation in diabetic and non-diabetic patients

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    OBJECTIVE: Presence of autonomic neuropathy in diabetic patients can alter the haemodynamic response to induction and tracheal intubation. This trial was conducted to compare this response in 30 non-diabetic (control group) and 30 diabetic patients including both insulin and non-insulin dependent. METHODS: A prospective, age matched case controlled study was conducted at the Aga Khan University Hospital, for one year. After pre-medication with tablet midazolam 7.5 mgs orally, patients received pethidine 0.8 mg kg(-1), thiopentone sodium 4 to 5 mg kg(-1) for induction and vecuronium 0.1 mg kg(-1) to facilitate tracheal intubation. Following manual ventilation with isoflurane 0.8% in oxygen 33% and nitrous oxide 66%, laryngoscopy and tracheal intubation was performed. Blood pressure (systolic, diastolic and mean) and heart rate responses were measured for 10 minutes. RESULTS: The systolic arterial pressure dropped by 9% after induction and rose by 16% after intubation in nondiabetics compared to 12% drop after induction and a rise of 10% after intubation in diabetics. No difference was seen in diastolic blood pressure which increased by 27% in ND compared to 22% in DB groups. The heart rate rose by 27% in non-diabetics compared to 17% in diabetics after intubation. CONCLUSION: The systolic, diastolic and mean blood pressure response was similar in the two groups. A greater fall in SAP was observed post intubation in the DB group. A significant difference was observed in the heart rate response which was less in the diabetic group

    Should the concept of highly skilled migration be redefined? A case analysis of Estonia

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    Despite receiving countries' growing favourable perceptions of highly skilled (labour) migrants, defining, and using the concept of high-skilled migration is a puzzling question. The uncertainty that results makes it difficult to quantify human capital, preventing worldwide evaluations of skills, and makes it challenging to evaluate immigration policy. In this thesis, three standard criteria are evaluated to provide a discussion on this phenomenon of highly skilled migration. The term "highly skilled" has been evaluated from a definitional perspective under the paradigm of academics, the global labour market and immigration policies. To assess the applicability of the criteria defining a "highly skilled", Estonia has used a case study to assess how the definitional approach differs from immigration policies and thus provide a critical analytical discussion on the relevancy of "highly skilled" in the new knowledge economy

    Behavioural intention of tourists towards volunteer tourism: A developing country perspective

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    Purpose: Although volunteer tourism has been studied via several theoretical lenses, little is known about the behavioural intention of potential volunteer tourists from developing nations. This study aimed to identify the behavioural intention of potential volunteer tourists and the factors motivating them. This study extends the theory of planned behaviour (TPB) to identify the potential volunteer tourists’ behavioural intentions by adding four motivations: altruism, personal development, escape, and travel. Methods: A total of 272 valid responses were collected through an online survey. SmartPLS 3.0 was used to test the hypotheses. Results: The findings indicate that attitude, perceived behavioural control, subjective norms, escape, and personal development positively influences potential volunteer tourists’ intention to take part in volunteer tourism programs. However, altruism and travel do not influence the potential volunteer tourists’ intention to take part in volunteer tourism programs. Implications: Volunteer tourism organisers will get help from the present study’s findings to design or improve volunteer tourism programs and activities accordingly, resulting in improved volunteer tourism experiences and, ultimately, impacting the tourists’ intention to take part in volunteer tourism programs

    Synthesis and Characterization of Organic-Inorganic Nanocomposite Poly-o-anisidine Sn(IV) Arsenophosphate: Its Analytical Applications as Pb(II) Ion-Selective Membrane Electrode

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    Poly-o-anisidine Sn(IV) arsenophosphate is a newly synthesized nanocomposite material and has been characterized on the basis of its chemical composition, ion exchange capacity, TGA-DTA, FTIR, X-RAY, SEM, and TEM studies. On the basis of distribution studies, the exchanger was found to be highly selective for lead that is an environmental pollutant. For the detection of lead in water a heterogeneous precipitate based ion-selective membrane electrode was developed by means of this composite cation exchanger as electroactive material. The membrane electrode is mechanically stable, with a quick response time, and can be operated over a wide pH range. The selectivity coefficients were determined by mixed solution method and revealed that the electrode is sensitive for Pb(II) in presence of interfering cations. The practical utility of this membrane electrode has been established by employing it as an indicator electrode in the potentiometric titration of Pb(II)

    Nutritional value of Pleurotus (Flabellatus) Djamor (R-22) cultivated on sawdusts of different woods

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    The sawdust of different woods were investigat ed for the cultivation of exotic strain of Pleurotus (flabellatus) djamor (R-22) to find out the efficiency of different nutrients including protein, fat, crude fiber, ash, dry matter and moisture. Among all type of nutrients, protein, fat, cr ude fiber, ash, dry matter and moisture of Pleurotus ostreatus on sawdust of different woods were observed. Protein was observed on cont rol treatment (cotton waste, kikar, mango, mixed sawdust, simbal and kail (21.89), (21.64), (21.34), (21.16), (21.03) and (20.75) % respectively. Fat was observed on control treatment (cotton waste, kikar, mango, mi xed sawdust, simbal and kail (0.80), (0.53), (0 .41), (0.33), (0.24) and (0.11)% respectively. Crude fiber was observed on control treatment (cotton waste, kikar, mango, mixed sawdust, simbal and kail (8.92), (8.45), (8.17), (7.96), (7.70) and (7.32) % respectively. Ash was observ ed on control treatment (cotton waste, kikar, mango, mixed sawdust, simbal and kail (7.65), (6.75), (6 .47), (6.39), (6.33) and (6.23%) respectively. Dry matter was observed on control treatment (cotton waste, kikar, mango, mixed sawdust, simbal and kail (6.47), (6.27), (6.13), (6.01), (5.87) and (5.67) % respectively. Moisture was observed on control treatment (c otton waste, kikar, mango, mixed sawdust, simbal and kail (84.55), (81.20), (79.85), (76.26), (74.35) and (71.14) % respectively. Oyster mushroom showed relatively more contents on control treatment cotton waste as compared to other substrates. The maximum protein, fat, crude fiber, ash, dry matter and moisture contents in Pleurotus (flabellatus) djamor (R-22) was obtained on Kikar sawdust .The lowest contents was obtained on kail sawdust

    Categorization and scaling of distinct gossypol classes with respect to gossypol content in cotton (Gossypium hirsutum L).

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    Gossypols are the pigment glands conferring resistance to insect pests; distributed on the plant body covering the stem, leaf, bract, calyx and carpel walls. The objective of the present study was to quantify the gossypol concentration on the unopened bolls of cotton and to devise a quantitative scaling for categorizing different gossypol classes in different genetic backgrounds through spectrophotometry. There were substantial differences among the P1, P2, F1, F2, BC1 and BC2 generations of the two crosses (HRVO-1 × Acala 63-74 and HRVO-1 × HG-142) for total gossypol and total gossypol (%). The mean total gossypol content in the glandless parent (Acala 63-74) and its F1, in a cross with the normal glanding parent (HRVO-1) was 0.04 mg.g-1 (2%) and 0.140 mg.g-1 (5%) respectively while in the high glanding parent (HG-142) and its F1 produced in a cross with the normal glanding parent it was 1.14 mg.g-1 (46%) and 0.88 mg.g-1 (35%) respectively. The mean total gossypol was estimated as 0.60 mg.g-1 (24%) in the commonly used normal glanding parent. From the data and the analytical procedure used for the quantification of gossypol clearly highlighted the importance of the application of these chemo-metric tools. This method of quantification is accurate and may be used in breeding programs to screen the progeny of cotton genotypes showing segregation for gossypol content.. Keywords: Gossypium hirsutum L; Gossypol glands; Cotton Bolls; Scaling; Quantification; Spectrophotometry

    An open-source software framework for the integrated simulation of structures in fire

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    The traditional methods to understand the development of elevated temperature in a structure, and also the associated structural response, are not representative of realistic fire scenarios. To provide a more accurate and realistic reflection of the fire development, the current paper develops a generic middleware which interfaces between the computational fluid dynamics (CFD) software Fire Dynamics Simulator (FDS) and the finite element (FE) analysis software OpenSees. This framework enables a fully integrated simulation of a realistic fire scenario including the heat transfer through the structure and the resulting thermo-mechanical response. The proposed framework is open-source and freely available and therefore can be used and further developed by researchers and practicing engineers and customised to their requirements. This paper shows validation against two sets of experimental results and one real fire incident. A number of different types of thermal boundary conditions such as gas temperatures and heat fluxes, are obtained from the CFD analysis and are then used in the subsequent heat transfer and thermo-mechanical analysis. The primary advantage of this computational tool is that it provides consultants and designers with the means to undertake large-scale projects requiring performance-based fire engineering solutions

    Estimation of blood loss during Caesarean section: an audit

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    Objective: To evaluate the blood ordering practice and blood transfusion for Caesarean sections at our institution and to compare the estimated blood loss between anaesthetists and obstetricians.Methods: A review of 126 patients undergoing both elective and emergency Caesarean section was undertaken in 2002. Information collected included the number of blood units cross-matched preoperatively, type of surgery (emergency or elective), type of anaesthesia, parity of the patient, estimated blood loss by both anaesthetists and obstetricians, intraoperative and postoperative transfusion within 48 hours and pre and post operative haemoglobin (Hb) and haemocrit (Hct).Results: A total of 215 units were cross-matched for 126 patients undergoing Caesarean section delivery. A small amount (9.5%) were transfused intraoperatively and 5.5% postoperatively. The average blood loss estimated by anaesthetists was 498 +/- 176 ml and that by obstetricians was 592 +/- 222 ml. The calculated blood loss based on patients blood volume and drop in Hct was 787 +/- 519 ml. The cross-match transfusion ratio was 9.7.CONCLUSION: Only 13% of our patients needed blood transfusion. The mean blood loss was estimated to be more by the obstetricians as compared to the anaesthetists. We recommend that the practice of routine cross-match practice prior to Caesarean section should be re-looked by institutions practicing obstetric anaesthesia
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