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941.
Although very developed in many sectors (databases, filesystems), access control schemes are still somewhat elusive when it comes to wireless sensor networks. However, it is clear that many WSN systems—such as healthcare and automotive ones—need a controlled access to data that sensor nodes produce, given its high sensitivity. Enforcing access control in wireless sensor networks is a particularly difficult task due to the limited computational capacity of wireless sensor nodes. In this paper we present a full-fledged access control scheme for wireless sensor data. We enforce access control through data encryption, thus embedding access control in sensor data units. We also propose a lightweight key generation mechanism, based on cryptographic hash functions, that allows for hierarchical key derivation. The suggested protocol only relies on simple operations, does not require interactions between nodes and data consumers and has minimal storage requirements.
Piervito ScagliosoEmail:

Alessandro Sorniotti   has a double MSc degree from Politecnico di Torino (Turin, Italy) in Computer Science and from EURECOM in Networking. He also obtained a Research Master diploma (DOA) in Networking and Distributed Systems from Université de Nice-Sophia Antipolis (UNSA, Nice, France). Alessandro has won a scholarship (bourse CIFRE) and he is a PhD candidate at ENST, working as a Research Associate at SAP Labs France. His current research topic is the study of protocols for Secret Exchange, Secret Matching and Secret Handshake. Refik Molva   is a full professor and the head of the Computer Communications Department at Institute Eurécom in Sophia Antipolis, France. His current research interests are the design and evaluation of protocols for security and privacy in self-organizing systems. He previously worked on several research projects on multicast and mobile network security, anonymity and intrusion detection. Beside security, he worked on distributed multimedia applications over high speed networks and on network interconnection. Prior to joining Eurécom, he worked in the Zurich Research Laboratory of IBM where he was one of the key designers of the KryptoKnight security system. He also worked as a consultant in security for the IBM Consulting Group. He has a PhD in Computer Science from the Paul Sabatier University in Toulouse (1986) and a BSc in Computer Science (1981) from Joseph Fourier University, Grenoble, France. Laurent Gomez   is a senior researcher at SAP Research France since 2001. He is currently involved in WASP and ATLAS projects. His research activities are focused on security and context-aware systems. Prior to joining SAP Research, Laurent Gomez worked as engineer at research projects for Ericsson. He has a strong background in security of mobile applications, with a focus on context-aware systems. Laurent holds a Engineer Degree in Computing Systems from ESSI (Ecole Superieure en Sciences Informatique), Nice France. Christophe Trefois   received his BSc degree in Communication Systems from the Ecole Polytechnique Fédérale de Lausanne (EPFL) in Switzerland in 2006. In 2008, he obtained his MSc degree in Communication Systems from EPFL. From March to August 2008, he worked as a Research Assistant at SAP Labs France in Sophia Antipolis. Christophe is currently working as an IT Consultant at Ernst & Young Luxembourg and is a member of the ISACA Lux Chapter. Annett Laube   joined SAP Research Security & Trust program in 2006. She is a senior researcher currently leading in the WASP project. Prior to joining SAP, she worked at IBM Scientific Center in Heidelberg in the areas of machine translation of natural languages and text mining. Later she worked as an IBM consultant for e-business and data warehouse. In parallel she wrote her PhD thesis about the translation of dependency structures in the transfer process from one natural language to another. She started to work for SAP in 2001 at SAP Labs Montreal/Quebec and worked as a software developer for Supply Chain Event Management. Piervito Scaglioso   received his MSc degree from Politecnico di Torino in 2006. He is currently enrolled as PhD student in the Department of Computer Science at the Politecnico di Torino. His research interests include: Policy-based system and their application to manage access control, access control for wireless sensor network and hierarchical key management scheme.   相似文献   
942.
On the basis of the fusion behavior of poly(vinyl chloride) (PVC), the influence of compounding route on the properties of PVC/(layered silicate) nanocomposites was studied. Four different compounding addition sequences were examined during the melt compounding of PVC with montmorillonite (MMT) clay, including (a) a direct dry mixing of PVC and nanoclay, (b) an addition of nanoclay at compaction, (c) an addition of nanoclay at the onset of fusion, and (d) an addition of nanoclay at equilibrium torque. Both unmodified sodium montmorillonite (Na+‐MMT) and organically modified montmorillonite (Org.‐MMT) clays were used, and the effect of the addition sequence of the clay during compounding on its dispersion in the matrix was evaluated by X‐ray diffraction and transmission electron miscroscopy. The surface color change, dynamic mechanical analysis, and flexural and tensile properties of PVC/clay nanocomposites were also studied. The experimental results indicated that both the extent of property improvement and the dispersion of nanoparticles in PVC/(layered silicate) nanocomposites are strongly influenced by the degree of gelation achieved in PVC compounds during processing. The addition of nanoclay to PVC must be accomplished at the onset of fusion, when PVC particles are reduced in size, in order to produce nanocomposites with better nanodispersion and enhanced mechanical properties. Overall, rigid PVC nanocomposites with unmodified clay (Na+‐MMT) were more thermally stable and exhibited better mechanical properties than their counterparts with organically modified clay (Org.‐MMT). J. VINYL ADDIT. TECHNOL., 2009. © 2009 Society of Plastics Engineers  相似文献   
943.
Water encapsulation using silica nanoparticles was assessed using two different types of single step mixing processes. The influential mixing characteristics have been determined. Direct mixing at high rotational speed requires high shear and vigorous stirring properties. Progressive water atomisation using gentle mixing process requires high atomisation pressure and rapid surface refreshing of the mixed material. Mechanisms of powder formation were also proposed. Encapsulation of micrometric water droplets in shell-like structure is respectively obtained by either progressive size reduction of macroscopic particulates or direct coating of pre-formed microscopic droplets. These mechanisms resulting from the interactions between a solid particle and a liquid highly depend on parameters such as particle's hydrophobicity, surface tension or kinetic energy.  相似文献   
944.
Two photocatalysts based on TiO2-pillared intercalated montmorillonite have been prepared by microwave for 10 min at 700 W or by furnace heating at 673 K. Montmorillonite pillaring with TiO2 increased the basal spacing to 14.7 Å (conventional heating) and 17.6 Å (microwave heating). XRD patterns of both materials showed the presence of 100% anatase with a slightly higher rate of crystallinity obtained through microwave calcination than by conventional heating at 673 K. The BET specific surface area of the microwave prepared photocatalyst (151 m2 g− 1) was 3 fold higher than those of the Degussa TiO2 P25. At pH = 5.8, the maximum adsorption capacity of Solophenyl red 3BL (a textile azo dye) on the TiO2-pillared montmorillonite calcined by microwave was 185 mg g− 1, whereas it was 1.4 and 3 fold lower on the TiO2-pillared montmorillonite calcined at 673 K, and on the Degussa TiO2 P25 respectively. The influence of pH on the adsorption of the dye depended on the pHZPC of the pillared montmorillonites.  相似文献   
945.
减少供热系统失水是节能的重要措施   总被引:1,自引:0,他引:1  
节约能源是我国的一项长期战略方针,建筑节能包括围护结构节能和供热采暖系统节能两个方面,而在采暖系统节能中。系统的失水能耗损失占很大比重,本文经过计算,每失1t热水需要多消耗16.38kgce。堵住失水的漏洞是供热企业应该关心的首要问题。不偷放热水,提高公民的法律意识,也是热力企业需要大力宣传的一个主题。  相似文献   
946.
With the establishment of a market economy, the deepening of market-oriented reforms, and an increased awareness of rights protection, the role of government as sole investor and manager of urban construction projects  相似文献   
947.
948.
949.
王实  刘颖 《电子质量》2004,(6):34-37
电磁兼容抗干扰测试仪器是电磁兼容测试中重要的一类测试仪器,但对于这些仪器的校准测试仍然没有国家计量检定规程或校准规范.本文对上述仪器的校准方法和校准仪器进行了介绍.  相似文献   
950.
本文给出了集成电路工艺流片、测试、封装成本的数学模型,并用设计成本量化模型计算了三种数字集成电路的成本,计算结果与实际结果吻合良好。  相似文献   
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