140,958 research outputs found

    March CRF: an Efficient Test for Complex Read Faults in SRAM Memories

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    In this paper we study Complex Read Faults in SRAMs, a combination of various malfunctions that affect the read operation in nanoscale memories. All the memory elements involved in the read operation are studied, underlining the causes of the realistic faults concerning this operation. The requirements to cover these fault models are given. We show that the different causes of read failure are independent and may coexist in nanoscale SRAMs, summing their effects and provoking Complex Read Faults, CRFs. We show that the test methodology to cover this new read faults consists in test patterns that match the requirements to cover all the different simple read fault models. We propose a low complexity (?2N) test, March CRF, that covers effectively all the realistic Complex Read Fault

    FollowMe: A Bigraphical Approach

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    In this paper we illustrate the use of modelling techniques using bigraphs to specify and refine elementary aspects of the FollowMe framework. This framework provides the seamless migration of bi-directional user interfaces for users as they navigate between zones within an intelligent environment

    Towards FollowMe User Profiles for Macro Intelligent Environments

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    We envision an Ambient Intelligent Environment as an environment with technology embedded within the framework of that environment to help enhance an users experience in that environment. Existing implementations , while working effectively, are themselves an expensive and time consuming investment. Applying the same expertise to an environment on a monolithic scale is very inefficient, and thus, will require a different approach. In this paper, we present this problem, propose theoretical solutions that would solve this problem, with the guise of experimentally verifying and comparing these approaches, as well as a formal method to model the entire scenario

    Theoretical background of rock failure at hydraulic seam fracture and aftereffect analysis

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    Purpose. Theoretical substantiation of the methodological foundations of possible effects and aftereffects identification of the hydraulic seam fracture (HSF) technology. Methods. The research structure and procedure includes: studying the power engineering aspect of the rock failure, the acoustical wave effects; thermodynamic analysis of rock failure, analysis of surfaces mechanoactivation at rock failure and aftereffect of the primary pore space self-development at the HSF due to the Rebinder’s effect. Findings. It was established that among the fundamental consistent patterns that determine the formation and development of the HSF technology aftereffects during formations mining, are the methodological provisions and criteria for failure parameters prediction and grinding effects, namely: the average and local energy density of geoenvironment destruction, efficiency of grinding, the average particle and pore size, the specific surface area, the specific energy consumption per unit of the resulting surface. The connection between the parameters of the acoustic wave and the size of the fractures, which forms the basis of the acoustic emission (AE) method, is experimentally confirmed. Originality. It is established that the database for evaluating the expected fracture effects in the working zone of the HSF is: AE activity, specific acoustic radiation, spectrum of signals, characteristic amplitudes under the condition of physical modeling on the model samples of the geoenvironment behavior. It is shown that the critical state of a substance corresponding to the beginning of failure at the microlevel should be considered from the standpoint of thermodynamics as a phase change (evaporation, sublimation) near the critical point, based on the temperature critical values and the specific energy of the phase change. The presence of surfaces mechanoactivation in the rock failure is experimentally proved. The hypothesis concerning the rock pore space development aftereffect during hydraulic seam fracture due to the Rebinder’s effect is presented. Practical implications. It is proposed to size up the degree of geoenvironment destruction in the process of the HSF by the Kd parameter, which is equal to the product of the maximum amplitude of acoustic signals on the total acoustic activity of the destruction zone. It is established that the conditions for rock failure at the HSF are determined by the relationship between the rock pressure P and the volume energy density W of the failure. It is shown that the level of surfaces mechanoactivation can be estimated by adsorption characteristics – the adsorption potential and the pH of the newly discovered surfaces.Мета. Теоретичне обґрунтування методологічних основ встановлення умов прояву можливих ефектів і пост-ефектів технології гідравлічного розриву пласта (ГРП). Методика. Структура та послідовність проведення дослідження включає вивчення енергетичного аспекту руйнування гірського масиву, дії акустичних хвиль, термодинамічний аналіз руйнування гірського масиву, аналіз механоактивації поверхонь при руйнуванні гірського масиву та пост-ефекту саморозвитку первинного пористого простору ГРП внаслідок дії ефекту Ребіндера. Застосовано метод акустичної емісії, потенціометрії та рН-метрії. Результати. Встановлено, що до числа фундаментальних закономірностей, які визначають формування і розвиток пост-ефектів технології ГРП при відпрацюванні продуктивних пластів, відносяться методичні положення й критерії для прогнозу показників руйнування та ефектів подрібнення, а саме: середньої та локальної густини енергії при руйнуванні геосередовища, ККД подрібнення, середній розмір часток і пор, питома поверхня, питомі витрати енергії на одиницю одержаної поверхні. Експериментально підтверджений зв’язок між параметрами акустичної хвилі та розміром тріщин, що складає основу методу акустичної емісії (АЕ). Наукова новизна. Встановлено, що базу інформації для оцінки очікуваних у робочій зоні ГРП ефектів руйнувань складають активність АЕ, питоме акустичне випромінювання, спектр сигналів, характерні амплітуди за умови фізичного моделювання поведінки геосередовища на модельних зразках. Визначено, що граничний стан речовини, що відповідає початку руйнування на мікрорівні, слід розглядати з позицій термодинаміки як фазовий перехід (випаровування, сублімація) поблизу критичної точки, виходячи із критичних значень температури і питомої енергії фазового переходу. Експериментально доведено наявність механоактивації поверхонь при руйнуванні гірського масиву. Висунута гіпотеза щодо пост-ефекту розвитку пористого простору гірського масиву при ГРП у контексті дії ефекту Ребіндера. Практична значимість. Запропоновано оцінювати ступінь руйнування геосередовища у процесі ГРП показником Кр, що дорівнює добутку максимальної амплітуди акустичних сигналів на сумарну акустичну активність зони руйнування. Встановлено, що умови руйнування гірського масиву при ГРП детермінуються співвідношенням між гірським тиском Р і об’ємною густиною енергії W деформації. Показано, що ступінь механоактивації поверхонь може бути оцінена за характеристиками адсорбції – потенціалом адсорбції та показником рН нововідкритих поверхонь.Цель. Теоретическое обоснование методологических основ установления условий проявления возможных эффектов и пост-эффектов технологии гидравлического разрыва пласта (ГРП). Методика. Структура и последовательность проведения исследования включает изучение энергетического аспекта разрушения горного массива, действия акустических волн, термодинамический анализ разрушения горного массива, анализ механоактивации поверхностей при разрушении горного массива и пост-эффекта саморазвития первичного пористого прострагства ГРП в результате действия эффекта Ребиндера. Применен метод акустической эмиссии, потенциометрии и рН-метрии. Результаты. Установлено, что к числу фундаментальных закономерностей, определяющих формирование и развитие пост-эффектов технологии ГРП при отработке продуктивных пластов, относятся методические положения и критерии для прогноза показателей разрушения и эффектов измельчения, а именно: средней и локальной плотности энергии при разрушении геосреды, КПД измельчения, средний размер частиц и пор, удельная поверхность, удельные затраты энергии на единицу полученной поверхности. Экспериментально подтверждена связь между параметрами акустической волны и размером трещин, что составляет основу метода акустической эмиссии (АЭ). Научная новизна. Установлено, что базу информации для оценки ожидаемых в рабочей зоне ГРП эффектов разрушений составляют актитивность АЭ, удельное акустическое излучение, спектр сигналов, характерные амплитуды при условии физического моделирования поведения геосреды на модельных образцах. Определено, что предельное состояние вещества, отвечающее началу разрушения на микроуровне, следует рассматривать с позиций термодинамики как фазовый переход (испарение, сублимация) вблизи критической точки, исходя из критических значений температуры и удельной энергии фазового перехода. Экспериментально доказано наличие механоактивации поверхностей при разрушении горного массива. Выдвинута гипотеза относительно пост-эффекта развития пористого пространства горного массива при ГРП в контексте действия эффекта Ребиндера. Практическая значимость. Предложено оценивать степень разрушения геосреды в процессе ГРП показателем Кр, который равен произведению максимальной амплитуды акустических сигналов на суммарную акустическую активность зоны разрушения. Установлено, что условия разрушения горного массива при ГРП детерминируются соотношением между горным давлением Р и объемной плотностью энергии W деформации. Показано, что степень механоактивации поверхностей может быть оценен по характеристикам адсорбции – потенциалом адсорбции и показателем рН новооткрытых поверхностей.The authors express their gratitude to Doctor of Physical and Mathematical Sciences Vilian Mykolayovych Bovenko for valuable advices when conducting research. In addition, thanks to Doctor of Engineering Sciences Anatolii Dmytrovych Aleksieiev for the opportunity to use a unique research unit of non-uniform triaxial load and research method revision. The authors thank to Candidate of Engineering Sciences Iryna Mykhailivna Yuriivska for consultations on the use of her original method of mechanoactivation study

    Lessons from helminth infections: ES-62 highlights new interventional approaches in rheumatoid arthritis

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    Parasitic worms are able to survive in their mammalian host for many years due to their ability to manipulate the immune response by secreting immunomodulatory products. It is increasingly clear that, reflecting the anti-inflammatory actions of such worm-derived immunomodulators, there is an inverse correlation between helminth infection and autoimmune diseases in the developing world. As the decrease in helminth infections due to increased sanitation has correlated with an alarming increase in prevalence of such disorders in industrialised countries, this "Hygiene Hypothesis" has led to the proposal that worms and their secreted products offer a novel platform for the development of safe and effective strategies for the treatment of autoimmune disorders. Here we review the anti-inflammatory effects of one such immunomodulator, ES-62 on innate and adaptive immune responses and the mechanisms it exploits to afford protection in the murine Collagen Induced Arthritis (CIA) model of rheumatoid arthritis (RA). As its core mechanism involves targeting of IL-17 responses, which despite being pathogenic in RA are important for combating infection, we discuss how its selective targeting of IL-17 production by Th17 and γδ T cells, whilst leaving that of CD49b+ Natural Killer (NK and NK T) cells intact, reflects the ability of helminths to modulate the immune system without immunocompromising the host. Exploiting helminth immunomodulatory mechanisms therefore offers the potential for safer therapies than current biologics, such as "IL-17 blockers", that are not able to discriminate sources of IL-17 and hence present adverse effects that limit their therapeutic potential

    3D UAV Trajectory and Communication Design for Simultaneous Uplink and Downlink Transmission

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    In this paper, we investigate the unmanned aerial vehicle (UAV)-Aided simultaneous uplink and downlink transmission networks, where one UAV acting as a disseminator is connected to multiple access points (AP), and the other UAV acting as a base station (BS) collects data from numerous sensor nodes (SNs). The goal of this paper is to maximize the system throughput by jointly optimizing the 3D UAV trajectory, communication scheduling, and UAV-AP/SN transmit power. We first consider a special case where the UAV-BS and UAV-AP trajectories are pre-determined. Although the resulting problem is an integer and non-convex optimization problem, a globally optimal solution is obtained by applying the polyblock outer approximation (POA) method based on the problem's hidden monotonic structure. Subsequently, for the general case considering the 3D UAV trajectory optimization, an efficient iterative algorithm is proposed to alternately optimize the divided sub-problems based on the successive convex approximation (SCA) technique. Numerical results demonstrate that the proposed design is able to achieve significant system throughput gain over the benchmarks. In addition, the SCA-based method can achieve nearly the same performance as the POA-based method with much lower computational complexity

    Numerical solution of the two-dimensional Helmholtz equation with variable coefficients by the radial integration boundary integral and integro-differential equation methods

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    This is the author's accepted manuscript. The final published article is available from the link below. Copyright @ 2012 Taylor & Francis.This paper presents new formulations of the boundary–domain integral equation (BDIE) and the boundary–domain integro-differential equation (BDIDE) methods for the numerical solution of the two-dimensional Helmholtz equation with variable coefficients. When the material parameters are variable (with constant or variable wave number), a parametrix is adopted to reduce the Helmholtz equation to a BDIE or BDIDE. However, when material parameters are constant (with variable wave number), the standard fundamental solution for the Laplace equation is used in the formulation. The radial integration method is then employed to convert the domain integrals arising in both BDIE and BDIDE methods into equivalent boundary integrals. The resulting formulations lead to pure boundary integral and integro-differential equations with no domain integrals. Numerical examples are presented for several simple problems, for which exact solutions are available, to demonstrate the efficiency of the proposed methods

    Ab initio spectroscopic characterization of the radical CH3_3OCH2_2 at low temperatures

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    Spectroscopic and structural properties of methoxymethyl radical (CH3_3OCH2_2, RDME) are determined using explicitly correlated ab initio methods. This radical of astrophysical and atmospheric relevance has not been fully characterized at low temperatures, which has delayed the astrophysical searches. We provide rovibrational parameters, excitations to the low energy electronic states, torsional and inversion barriers and low vibrational energy levels. In the electronic ground state (X2^2A), which appears "clean" from non-adiabatic effects, the minimum energy structure is an asymmetric geometry which rotational constants and dipole moment have been determined to be A0_0=46718.6745 MHz, B0_0=10748.4182 MHz, and C0_0=9272.5105 MHz, and 1.432 D (μA\mu_A=0.6952 D, μB\mu_B=1.215 D, μC\mu_C=0.3016 D), respectively. A variational procedure has been applied to determine torsion-inversion energy levels. Each level splits into 3 subcomponents (A1_1/A2_2 and E) corresponding to the three methyl torsion minima. Although the potential energy surface presents 12 minima, at low temperatures, the infrared band shapes correspond to a surface with only three minima because the top of the inversion Vα^{\alpha} barrier at α=0{\alpha}=0^{\circ} (109 cm1^{-1}) stands below the zero point vibrational energy and the CH2_2 torsional barrier is relatively high (\sim2000 cm1^{-1}). The methyl torsion barrier was computed to be \sim500 cm1^{-1} and produces a splitting of 0.01 cm1^{-1} of the ground vibrational state

    Numerical solution of the two-dimensional Helmholtz equation with variable coefficients by the radial integration boundary integral and integro-differential equation methods

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    This is the author's accepted manuscript. The final published article is available from the link below. Copyright @ 2012 Taylor & Francis.This paper presents new formulations of the boundary–domain integral equation (BDIE) and the boundary–domain integro-differential equation (BDIDE) methods for the numerical solution of the two-dimensional Helmholtz equation with variable coefficients. When the material parameters are variable (with constant or variable wave number), a parametrix is adopted to reduce the Helmholtz equation to a BDIE or BDIDE. However, when material parameters are constant (with variable wave number), the standard fundamental solution for the Laplace equation is used in the formulation. The radial integration method is then employed to convert the domain integrals arising in both BDIE and BDIDE methods into equivalent boundary integrals. The resulting formulations lead to pure boundary integral and integro-differential equations with no domain integrals. Numerical examples are presented for several simple problems, for which exact solutions are available, to demonstrate the efficiency of the proposed methods

    Changes in endotoxin levels in T2DM subjects on anti-diabetic therapies

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    Introduction Chronic low-grade inflammation is a significant factor in the development of obesity associated diabetes. This is supported by recent studies suggesting endotoxin, derived from gut flora, may be key to the development of inflammation by stimulating the secretion of an adverse cytokine profile from adipose tissue. Aims The study investigated the relationship between endotoxin and various metabolic parameters of diabetic patients to determine if anti-diabetic therapies exerted a significant effect on endotoxin levels and adipocytokine profiles. Methods Fasting blood samples were collected from consenting Saudi Arabian patients (BMI: 30.2 ± (SD)5.6 kg/m2, n = 413), consisting of non-diabetics (ND: n = 67) and T2DM subjects (n = 346). The diabetics were divided into 5 subgroups based on their 1 year treatment regimes: diet-controlled (n = 36), metformin (n = 141), rosiglitazone (RSG: n = 22), a combined fixed dose of metformin/rosiglitazone (met/RSG n = 100) and insulin (n = 47). Lipid profiles, fasting plasma glucose, insulin, adiponectin, resistin, TNF-α, leptin, C-reactive protein (CRP) and endotoxin concentrations were determined. Results Regression analyses revealed significant correlations between endotoxin levels and triglycerides (R2 = 0.42; p < 0.0001); total cholesterol (R2 = 0.10; p < 0.001), glucose (R2 = 0.076; p < 0.001) and insulin (R2 = 0.032; p < 0.001) in T2DM subjects. Endotoxin showed a strong inverse correlation with HDL-cholesterol (R2 = 0.055; p < 0.001). Further, endotoxin levels were elevated in all of the treated diabetic subgroups compared with ND, with the RSG treated diabetics showing significantly lower endotoxin levels than all of the other treatment groups (ND: 4.2 ± 1.7 EU/ml, RSG: 5.6 ± 2.2 EU/ml). Both the met/RSG and RSG treated groups had significantly higher adiponectin levels than all the other groups, with the RSG group expressing the highest levels overall. Conclusion We conclude that sub-clinical inflammation in T2DM may, in part, be mediated by circulating endotoxin. Furthermore, that whilst the endotoxin and adipocytokine profiles of diabetic patients treated with different therapies were comparable, the RSG group demonstrated significant differences in both adiponectin and endotoxin levels. We confirm an association between endotoxin and serum insulin and triglycerides and an inverse relationship with HDL. Lower endotoxin and higher adiponectin in the groups treated with RSG may be related and indicate another mechanism for the effect of RSG on insulin sensitivity
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