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51st Annual IEEE/ACM International Symposium on Microarchitecture (MICRO)

作者： Qureshi, Moinuddin K. Georgia Inst Technol Atlanta GA 30332 USA

ISBN: (纸本)9781538662403

Modern processors share the last-level cache between all the cores to efficiently utilize the cache space. Unfortunately, such sharing makes the cache vulnerable to attacks whereby an adversary can infer the access pattern of a co-running application by carefully orchestrating evictions using cache conflicts. Conflict-based attacks can be mitigated by randomizing the location of the lines in the cache. Unfortunately, prior proposals for randomized mapping require storage-intensive tables and are effective only if the OS can classify the applications into protected and unprotected groups. The goal of this paper is to mitigate conflict-based attacks while incurring negligible storage and performance overheads, and without relying on OS support. This paper provides the key insight that randomized mapping can be accomplished efficiently by accessing the cache with an encrypted address, as encryption would cause the lines that map to the same set of a conventional cache to get scattered to different sets. This paper proposes CEASE, a design that uses Low-Latency Block-Cipher (LLBC) to translate the physical line-address into an encrypted line-address, and accesses the cache with this encrypted line-address. We analyze efficient designs for LLBC that can perform encryption and decryption within two cycles. We also propose CEASER, a design that periodically changes the encryption key and performs dynamic-remapping to improve robustness. CEASER provides strong security (tolerates 100+ years of attack), has low performance overhead (1% slowdown), requires a storage overhead of less than 24 bytes for the newly added structures, and does not need any OS support.

关键词： programmable logic arrays Encryption Program processors Timing Indexes

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An ANTLR-Based Approach to Compiling the Programing Language of Insect Intelligent Building

An ANTLR-Based Approach to Compiling the Programing Language...

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Chinese Automation Congress (CAC)

作者： Wenjie Chen Qiliang Yang Jianchun Xing Shuo Zhao Guangtong Xue Song Wang College of Defense Engineering Army Engineering University of PLA Nanjing China Guangzhou Design Station of Army Academ Guangdong China

I 2 B(Insect Intelligent Building) platform is a new type of building intelligent system. Lattice is a specialized programming language for I 2 B application development that we proposed earlier. Unfortunately, compiling Lattice codes into target codes running on the I 2 B hardware platform is still an unsolved problem. This paper proposes a compilation framework for Lattice. The entire compilation process is divided into multiple levels, and each level performs a specific translation work. We design key compiling algorithms for special language elements in Lattice, i.e., neighborhood interactive variables and higher-order operators. We conduct an experiment using a network summation case program in I 2 B. The experimental result shows our proposed compilation approach is effective.

关键词： Lattices Buildings C languages Syntactics Programming Domain specific languages programmable logic arrays

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Linear-Time and Efficient Distributed Algorithms for List Coloring Graphs on Surfaces

Linear-Time and Efficient Distributed Algorithms for List Co...

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Annual IEEE Symposium on Foundations of Computer Science

作者： Luke Postle Department of Combinatorics and Optimization University of Waterloo Waterloo Canada

In 1994, Thomassen proved that every planar graph is 5-list-colorable. In 1995, Thomassen proved that every planar graph of girth at least five is 3-list-colorable. His proofs naturally lead to quadratic-time algorithms to find such colorings. Here, we provide the first linear-time algorithms to find such colorings. For a fixed surface S, Thomassen showed in 1997 that there exists a linear-time algorithm to decide if a graph embedded in S is 5-colorable and similarly in 2003 if a graph of girth at least five embedded in S is 3-colorable. Using the theory of hyperbolic families, the author and Thomas showed such algorithms exist for list-colorings. Around the same time, Dvorak and Kawarabayashi also provided such algorithms. Moreover, they gave an algorithm to find such colorings (if they exist). Here we provide the first such algorithm which is fixed parameter tractable with genus as the parameter; indeed, we provide a linear-time algorithm to find such colorings. In 1988, Goldberg, Plotkin and Shannon provided a deterministic distributed algorithm for 7-coloring n-vertex planar graphs in O(log n) rounds. In 2018, Aboulker, Bonamy, Bousquet, and Esperet provided a deterministic distributed algorithm for 6-coloring n-vertex planar graphs in polylogarithmic rounds. Their algorithm in fact works for 6-list-coloring. They also provided a polylogarithmic algorithm for 4-list-coloring triangle-free planar graphs. Chechik and Mukhtar independently obtained such algorithms for ordinary coloring in O(log n) rounds, which is best possible in terms of running time. Here we provide the first polylogarithmic deterministic distributed algorithms for 5-coloring n-vertex planar graphs and similarly for 3-coloring planar graphs of girth at least five. Indeed, these algorithms run in O(log n) rounds, work also for list-colorings, and even work on a fixed surface (assuming such a coloring exists).

关键词： Distributed algorithms Complexity theory Computational modeling Color programmable logic arrays Distributed computing Computer science

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Electromagnetic Analysis and Performance Comparison of Fully 3D-printed Antennas

Electromagnetic Analysis and Performance Comparison of Fully...

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Progress in Electromagnetic Research Symposium (PIERS)

作者： R. Colella F. Chietera L. Catarinucci A. Casula G. Montisci G. Gatto A. Michel P. Nepa H. Rogier University of Salento Lecce Italy University of Cagliari Cagliari Italy University of Pisa Pisa Italy Internet Technology and Data Science Lab Ghent University Gent Belgium

ISBN: (数字)9781728134031

ISBN: (纸本)9781728134048

In this work, the possibility of directly prototyping antennas by exploiting additive manufacturing 3D-printing technology is investigated. In particular, the availability of printable filaments with interesting conductive properties allows for printing of even the antenna conductive elements. Three samples of a 2.45 GHz microstrip patch antenna have been 3D-printed by using different approaches and materials, and their performance evaluated and compared. In particular, the same dielectric substrate printed in polylactic acid (PLA) has been adopted in all cases, whilst copper tape and two different conductive filaments have been used to realize the conductive parts of the three antenna samples, respectively. Even if an expected radiation efficiency reduction has been observed for the conductive filament case, the comparative analysis clearly demonstrates that 3D-printing technology can be exploited to design working fully-printed antennas, including the conductive parts.

关键词： Substrates programmable logic arrays Conductivity Springs Printing Patch antennas

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Banana/Sisal Fibers Reinforced Poly(lactic acid) Hybrid Biocomposites;Influence of Chemical Modification of BSF Towards Thermal Properties

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POLYMER COMPOSITES 2017年第6期38卷 1053-1062页

作者： Asaithambi, Balakrishnan Ganesan, Gowri Shankar Kumar, Srinivasan Ananda Annamalai Univ Dept Mfg Engn Chidambaram Tamil Nadu India Anna Univ Dept Chem Madras Tamil Nadu India

The present work focused on thermal behavior of biocomposites based on poly(lactic acid) (PLA) reinforced with untreated and benzoyl peroxide (BP) treated banana/sisal fibers (BSF) combination. Fabrication of biocomposites was performed by extrusion followed by injection molding. Fourier transformed infrared (FTIR) spectral technique ascertained the nature of bonding between BSF and PLA. The thermal properties of virgin PLA, UT-BSF/PLA, and BP-T-BSF/PLA composites were studied by DSC and TGA analysis. DSC analysis indicated no significant changes in the glass transition temperature (T-g) and melting temperature (T-m) of virgin PLA, UT-BSF/PLA, and BP-T-BSF/PLA composites and no sign of crystallization for both virgin PLA, UT-BSF/PLA composites. However, crystallization was observed in BP-T-BSF/PLA composites. The BP-T-BSF/PLA composite exhibited a delayed thermal degradation pattern from TGA analysis when compared to that of UT-BSF/PLA composites and virgin PLA as well. Further, the effect of BSF treatment and hybridization of BSF with PLA on the degree of crystallinity (X-c) were explored in detail. The above said composites were also investigated through scanning electron microscope (SEM) micrographs to examine the adhesion between the PLA and BSF. In addition, the results of SEM acquired are in good agreement with the data resulted from FTIR and thermal characterization. (C) 2015 Society of Plastics Engineers

关键词： poly(lactic acid) Scanning Electron Microscope programmable logic arrays Virginity Thermal properties Composites BIOCOMPOSITE chemical modification

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Degradation Behavior of Electrospun PLA and PLA/CNT Nanofibres in Aqueous Environment

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JOURNAL OF NANOMATERIALS 2018年第Pt.2期2018卷 8796583-1-8796583-15页

作者： Magiera, Anna Markowski, Jaroslaw Pilch, Jan Blazewicz, Stanislaw AGH Univ Sci & Technol Dept Heat Engn & Environm Protect Fac Met Engn & Ind Comp Sci 30 Mickiewicza Ave PL-30059 Krakow Poland Med Univ Silesia Sch Med Laryngol Dept 20 Francuska Str PL-40752 Katowice Poland AGH Univ Sci & Technol Fac Mat Sci & Ceram Dept Biomat 30 Mickiewicza Ave PL-30059 Krakow Poland

The aim of the work was to compare the degradation behavior of electrospun nanofibres obtained from pure poly(lactic acid) (PLA) and modified with carbon nanotubes (CNTs) in aqueous environment. The nanofibres in the form of mats were manufactured using the electrospinning technique (ES) with potential biomedical application. To investigate the degradation behavior, one-component and composite (containing CNTs) nanofibres were compared using scanning electron microscopy (SEM), water contact angle measurements, differential scanning calorimetry (DSC), and mechanical testing. The changes in their morphology, structure, and selected physical and mechanical properties during incubation up to 14 days were analysed. Two types of CNTs differing in concentration of surface functional groups were used to modify the PLA nanofibres. PLA and composite nanofibres (PLA + CNT) during incubation underwent swelling and partial degradation due to the penetration of water into polymer matrix. Changes in the mechanical properties of composite mats were higher than those observed for pure PLA mats. After 14-day incubation, samples retained from 47 to 78% of their initial tensile strength, higher for PLA samples. Morphological changes in pure PLA nanofibres were more dynamic than in composite nanofibres. No significant changes in crystallinity, wettability, and porosity of the samples occurred.

关键词： Degradation Behavior Electrospun PLA and PLA/CNT Nanofibres Aqueous Environment Composites programmable logic arrays Incubation methylallyl trisulfide Nanofibres

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Effect of Organically Modified Montmorillonite (OMMT) on Biodegradation of PS:PLA and PS:PLA:OMMT Using Phanerochaete chrysosporium

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POLYMER COMPOSITES 2017年第7期38卷 1292-1301页

作者： Shimpi, Navinchandra Borane, Mahesh Kadam, Meghraj Mishra, Satyendra Univ Mumbai Dept Chem Bombay Maharashtra India North Maharashtra Univ Univ Inst Chem Technol Jalgaon Maharashtra India North Maharashtra Univ Sch Life Sci Jalgaon Maharashtra India

The environmental issues of synthetic polymers have been resolved using biodegradation under controlled conditions. The degradation study of polymeric composites of (a) polystyrene (PS) and poly(lactic acid) (PLA) (PS:PLA), and (b) PS:PLA filled with organically modified montmorillonite (OMMT) (PS:PLA:OMMT) was carried out using Phanerochaete chrysosporium. PLA was synthesized using L-lactic acid under controlled ultrasound cavitation technique, dried and added to a solution of PS. Surface of montmorillonite (MMT) was modified using column chromatographic technique to improve d-spacing up to 31.5 angstrom. The sheets of PS:PLA and PS:PLA:OMMT were subjected to degradation study in minimal medium using P. chrysosporium micro-organism under controlled conditions up to 28 days. The growth of micro-organism and fractures inside the polymer matrix before and after degradation was observed using scanning electron microscope. Change in extracellular protein content, biomass production, and % degradation with respect to time of incubated samples have been also studied. It was found that the PS:PLA:OMMT (at 5 phr OMMT content) and PS:PLA (at 30% PLA) composites show an increment in degradation. The presence of OMMT leads to faster degradation of PS:PLA:OMMT nanocomposites, which decreases in mechanical property by 30% of PLA and 5 wt% of OMMT content. (C) 2015 Society of Plastics Engineers

关键词： Organo-modified montmorillonite Phanerochaete chrysosporium Controlled conditions programmable logic arrays modified montmorillonite Environmental issues Microbes Synthetic Polymer biodegradation L-Lactic Acid Polystyrenes

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Tailoring Heat-Seal Properties of Biodegradable Polymers through Melt Blending

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INTERNATIONAL POLYMER PROCESSING 2017年第5期32卷 606-613页

作者： Tabasi, R. Y. Ajji, A. Polytech Montreal Dept Chem Engn Campus Univ Montreal 2900 Boul Edouard Montpetit Montreal PQ H3T 1J4 Canada

In this study, we address heat-seal properties of poly (lactic acid) (PLA), blended with Poly (butylene adipate-co-terephthalate) (PBAT). The objective is to correlate blends crystalline structure and morphology to corresponding heat-seal of blends films. The SEM micrographs show a two-phase elongated morphology where stretched ellipsoids developed through elongational flow during the cast film process. To distinguish the effect of crystallization, we also prepared amorphous and crystalline PBAT films and then compared them to blends with PLA. Heat-sealed areas were created by putting film surfaces in intimate contact for 1 s at the pressure of 0.5 N/mm(2) or Pa and in the temperature range of 70 to 140 degrees C. Thermal analysis shows that the crystalline structure of PBAT has a significant effect on shifting its heat-seal initiation temperature (T-si) up to 20 degrees C. Regarding the blends, incorporation of PBAT as a dispersed phase lowers Tsi of blend samples. Here, gradual decrease in PBAT crystallinity caused by the hindering effect of PLA rigid molecules correlates with the shift in heat-seal initiation temperature. As mentioned above, elongated disperse morphology with higher aspect ratio of the dispersed phase compared to spherical dispersed domain, is formed through film cast process. This enhances the adhesion process by providing higher contact area. The blends also show higher toughness and better puncture resistance, which is an asset for flexible packaging applications and would enhance the mechanical performance of the seal layer.

关键词： crystal structure biodegradable polymer Mechanical properties Melt blending Films programmable logic arrays protactinium CONTACT AREA Blends Film processing

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Influence of Temperature on Viscoelastic-Viscoplastic Behavior of Poly(lactic acid) Under Loading-Unloading

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POLYMER ENGINEERING AND SCIENCE 2017年第3期57卷 239-247页

作者： Dusunceli, Necmi Drozdov, Aleksey D. Theilgaard, Naseem Aksaray Univ Dept Mech Engn TR-68100 Aksaray Turkey Aalborg Univ Dept Mech & Mfg Engn DK-9220 Aalborg Denmark Danish Technol Inst Ctr Plast Technol DK-2630 Taastrup Denmark

Experimental data are reported on poly(lactic acid) (PLA) in tensile loading-unloading tests and relaxation tests under stretching and retraction at temperatures ranging from room temperature up to 508C. Two characteristic features of the time-dependent response of PLA are revealed: (i) with a decrease in minimum stress under retraction at a fixed temperature, relaxation curves change their shape from monotonically decaying with time (simple relaxation), to non-monotonic (mixed relaxation) to monotonically increasing (inverse relaxation) and (ii) with an increase in temperature, inverse relaxation after unloading down to the zero stress evolves into mixed relaxation with a pronounced shift of the peak position to smaller relaxation times. Constitutive equations are derived for the mechanical behavior of PLA, and adjustable parameters in the stress-strain relations are found by fitting the observations. Ability of the model to predict the time-dependent response under cyclic deformation is confirmed by numerical simulation. (C) 2016 Society of Plastics Engineers

关键词： stress-strain relations adjustable parameter Intercostal Retractions Constitutive equations time-dependent Relaxation programmable logic arrays relaxation Stretch UNLOADING Temperature LOADING AND UNLOADING poly(lactic acid) Mechanical properties

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Controlling the stereostructure of non-planar ring to induce the transition from plastic to elastomer in poly(butylene adipate-co-1,4-cyclohexane dicarboxylate) and implement of polylactic acid toughness

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POLYMER ENGINEERING AND SCIENCE 2017年第12期57卷 1277-1284页

作者： Qiu, Jia Liu, Fei Zhang, Junwu Chen, Jing Na, Haining Zhu, Jin Chinese Acad Sci Ningbo Key Lab Polymer Mat Ningbo Inst Mat Technol & Engn Ningbo 315201 Zhejiang Peoples R China

The controllable polyesters with high overall performance are obtained by tuning the stereostructure of 1,4-cyclohexylene ring moieties (CHRMs) in poly(butylene adipate-co-1,4-cyclohexanedicarboxylate) (PBAC). After increasing the number of irregular cis-CHRMs in the polyester, PBAC can transform from semicrystalline polymer to amorphous one. PBAC with 58% cis-CHRMs starts to exhibit good elasticity with shape recovery of 60% at 250% deformation, indicating the transition from plastic to thermoplastic elastomer. Through blending with polylactic acid (PLA), the elastic PBAC greatly enhances the impact strength of PLA to 7.5 kJ/m(2). While the tensile elongation at break is dramatically improved to 161% with the addition of plastic PBAC. The mechanism related to the stereostructure of non-planar ring of PBAC on the properties of PLA is also analyzed. Therefore, this research suggests a particular way to build non-planar ring contained polyesters to modify PLA with high toughness. POLYM. ENG. SCI., 57:1277-1284, 2017. (c) 2017 Society of Plastics Engineers

关键词： Impact strengths dicarboxylate RINGS TOUGHNESS rings Plastics programmable logic arrays elastic bodies Annulus Polyesters Ring device polybutene Elongation at break poly(lactic acid)

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