134 research outputs found

    Novi hemijski dodatak svežem betonu za izvođenje tunelske obloge u ekstremnim zimskim uslovima

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    A new type of calcium-nitrate and urea-based chemical admixture is proposed, in order to maintain the compressive strength of fresh concrete exposed to very low temperatures (below to - 250C), including a sudden transition to positive temperatures at an early age. The applied admixture has no negative effect on compressive strength of specimens cured in water at 200C. When it is cured under three different frost regimes, concrete specimens with admixture show over three times higher compressive strength, in comparison to specimens without admixture. The implications of such improved concrete composition are discussed in reference to the tunnel lining design.U radu se predlaže novi tip hemijskog dodatka betonu na bazi kalcijum-nitrata i uree, sa ciljem održavanja čvrstoće na pritisak svežeg betona izloženog vrlo niskim temperaturama (do -250C), uključujući i uticaj iznenadnih velikih temperaturnih amplituda (prelaze od negativnih ka pozitivnim temperaturama). Primenjeni dodatak ne utiče nepovoljno na čvrstoću na pritisak uzoraka betona negovanih u izotermalnim uslovima na temperaturi od 200C. Kada se svež beton izloži uticaju različitih režima mraza, uzorci sa dodatkom pokazuju gotovo tri puta veću pritisnu čvrstoću u poređenju sa uzorcima bez dodatka. Primena betona sa predloženim aditivom u praksi razmatra se u odnosu na postojanost i stabilnost tunelske obloge sa prskanim betonom

    Strategic Management and its Effects on Serbian Wood Industry

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    According to the available data on economic trends in Serbia, it is noticeable that companies in wood in-dustry do not use their capacities to the maximum. Furthermore, a significant number of newly founded small en-terprises, shortly after their establishment, go bankrupt or go into liquidation. Research works that have beenconducted so far have indicated that, most commonly, company deterioration is caused by a lack of strategic ap-proach in business management and company development. The aim of this paper is to gain an insight into the ex-tent to which wood industry enterprises apply strategic approach (their vision, mission and development strategies)when making business decisions, as well as the effects of such approach. This will be achieved by analyzing col-lected questionnaires and interviews with competent experts from wood industry monitoring institutions. Besides,SWOT and PESTLE analyses of the surveyed companies will be conducted. Furthermore, possible solutions forovercoming weaknesses and threats emerging in Serbian wood industry development will be indicated. Likewise,the possibilities for encouraging industry development and increasing its competitiveness level will be presented

    RDMA is Turing complete, we just did not know it yet!

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    It is becoming increasingly popular for distributed systems to exploit offload to reduce load on the CPU. Remote Direct Memory Access (RDMA) offload, in particular, has become popular. However, RDMA still requires CPU intervention for complex offloads that go beyond simple remote memory access. As such, the offload potential is limited and RDMA-based systems usually have to work around such limitations. We present RedN, a principled, practical approach to implementing complex RDMA offloads, without requiring any hardware modifications. Using self-modifying RDMA chains, we lift the existing RDMA verbs interface to a Turing complete set of programming abstractions. We explore what is possible in terms of offload complexity and performance with a commodity RDMA NIC. We show how to integrate these RDMA chains into applications, such as the Memcached key-value store, allowing us to offload complex tasks such as key lookups. RedN can reduce the latency of key-value get operations by up to 2.6x compared to state-of-the-art KV designs that use one-sided RDMA primitives (e.g., FaRM-KV), as well as traditional RPC-over-RDMA approaches. Moreover, compared to these baselines, RedN provides performance isolation and, in the presence of contention, can reduce latency by up to 35x while providing applications with failure resiliency to OS and process crashes.Comment: Updated to NSDI 2022 versio

    Legal certainty and taxation: The problem of retroactive interpretation

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    This article shows that the principle of legality of a tax norm is not exhausted in its 'source' component (i.e. that the norm is enacted by parliament) but also encompasses the 'content' element - a set of requirements for it to be deemed as good law. It is not just retroactivity of a law that is an issue, but legal certainty is also jeopardized by retroactive interpretation implying changes in interpretation of the same norm by authorities who understood it for a long period in a different sense. A threat to legal certainty also exists when a provision that was dormant for years is suddenly applied. A case study shows that the Serbian Parliament issued an authentic interpretation of a tax norm to assert essentially a different interpretation compared to the one well-established in the past, in order to solve a particular case, while a court used that interpretation to pass judgment in a pending case. Within the EU we find notable cases where not only are norms attributed a certain meaning from their inception, even though 60 years may have passed from their initial introduction to the possibility of the existence of a 'new meaning' being suggested for the first time, but taxpayers are made to suffer the consequences of the new interpretation. Had the legislator been able to pay more attention to the content of the bills and apply a more comprehensive approach to current issues, the legal certainty, in terms of avoiding 'innovative' retroactive interpretations, could be preserved

    MODIFIED INTERNAL MODEL CONTROL FOR A THERAPEUTIC ROBOT

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    We present the use of the modified internal model controller (MIMC) and the “Probability Tube” (PT) action representation for robot-assisted upper extremities training of hemiplegic patients. The robot-assisted training session has two phases. During the first "demonstration" phase the robot learns from the therapist the target path through examples. In the second "exercise" phase the robot assists a patient to follow the target path. During this process, the control limits the interface force between the robot and the hand to be below the preset threshold (F = 50 N). The system allows the assessment of the range of movement, the positional error between the target and the reached position, the amount of added assistance (the interface force between the hand and the robot). We demonstrate the operation in two hemiplegic patients. The patients and therapist suggested after the tests that the new system is straightforward and intuitive for clinical applications

    Semantic Search Engine as tool for clinical decision support in Register for Acute Coronary Syndrome

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    This paper presents the implementation and use of Semantic Search Engine (SSE) as part of knowledge management system functionalities in Register for Acute Coronary Syndrome (REACS). REACS SSE is part of a clinical decision support system and is used as an aid in decision making in clinical processes related to the care and treatment of patients with Acute Coronary Syndrome (ACS)

    Early Leaf Removal Increases Berry and Wine Phenolics in Cabernet Sauvignon Grown in Eastern Serbia

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    Cluster zone leaf removal is a well-established viticulture practice for improving cluster mi-croclimate and wine quality in cooler climates, while its efficacy in warmer conditions is less is known. Here we compared the effect of early (ELR, after fruit set; diameter of berries 3–5 mm) and late (LLR, beginning of veraison) leaf removal on berry composition and wine phenolic profile of grapevine (Vitis vinifera L.) variety Cabernet Sauvignon grown in a temperate, warmer region of Eastern Serbia. Compared to the control (no leaf removal), both leaf removal treatments increased the sugar content in fresh juice and alcohol concentration in wine. Over three consecutive years (2011–2013) markedly different in temperature and rainfall, ELR was clearly most effective in decreasing weights of cluster and of one berry, and in increasing of skin share in a berry. The content of total phenols, tartaric acid esters, anthocyanins, and flavanols in berry skin and wine was the highest in ELR treatment. ELR prominently modified the phenolic profile: Increasing flavanols, myricetin and quercetine in skin and wine, and anthocyanins, peonidin-3-glucoside in skin and delphinidin-3-glucoside in wine. This work demonstrated that early leaf removal positively influenced the chemical composition of berries and wine of Cabernet Sauvignon and might be recommended for practice in the temperate warm conditions

    MOCAB PAVILLION: crystal, canopy and line [STRAND 2022]

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    Unlike the Museum's architecture, which dominates the border between green (the park) and blue (the sky), the designed pavilion feels like an unobtrusive curved floating line, like a hinterland that only emphasizes the weight of the white crystal with its own immediate surroundings. Contrary to the monumentality and weight with which the Museum participates in the landscape of the city on a macro level, the newly designed pavilion aims to become an instrument of communication of the Museum with the immediate park environment, on a micro scale

    Transferring COVID-19 Challenges into Learning Potentials: Online Workshops in Architectural Education

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    The paper addresses the shift in architectural education regarding the need to develop new approaches in teaching methodology, improve curricula, and make advancements in new learning arenas and digital environments. The research is based on the assumption that online workshops could offer a unique learning experience for students in higher education. Accordingly, workshops are considered an essential element in teaching emergency design. As a result, this can produce broader and more innovative solutions to COVID-19 challenges regarding social distancing, limited movements, regulated use of public space, and suspended daily activities. The theoretical notions of emergency design and education for sustainable design enabled the identification of research perspectives and spatial levels to be taken as a starting point of the workshop “COVID-19 Challenges: Architecture of Pandemic” that was conducted by the University of Belgrade—Faculty of Architecture in April 2020. The critical review of the workshop’s procedural and substantial aspects led to identifying four main COVID-19 design challenges perceived in performance, innovation, alteration, and inclusion. Additionally, the paper’s findings concern the identification of learning potentials and limitations arising from a current topic affecting global society, for which neither solutions nor adequate answers in the field of architecture and urbanism have been found
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