Lightweight Matrix Research Articles

A natural multifunction and multiscale hierarchical matrix as a drug-eluting scaffold for biomedical applications.

Sea urchin spines are biogenic single crystals of magnesium calcite that are stiff, strong, damage tolerant and light and have a bicontinuous porous structure. Here, we showed that the removal of their intraskeletal organic matrix materials did not affect the compressive mechanical properties and generated an open porosity. This matrix was able to adsorb and release oxytetracycline, a broad-spectrum antibiotic. The drug-loaded sea urchin matrix induced bacterial cell death after 4 and 8 hours of incubation of both Gram-negative E. coli and Gram-positive S. aureus strains and this process induces an inhibition of bacterial cell adhesion. In conclusion, this study shows that thermally treated sea urchin spines are a compressive resistant and lightweight matrix able to load drugs and with potential use in spine fusion, a challenging application that requires withstanding high compressive loading.

A Lightweight Matrix Factorization for Recommendation With Local Differential Privacy in Big Data

The proliferation of various items recommended by Internet-based systems has resulted in the exponential growth of the number of ratings in the big data era. Recent advances in matrix factorization have made it an effective way to process these ratings for recommendations. However, we confront a challenge in deploying a matrix factorization model for recommendations in big data that arises from the typically resource-constrained local devices regarding their storage space and computing capacity. This paper proposes a novel lightweight matrix factorization for recommendations. Our scheme deploys shard grandients training on user local internet of things(IoT) devices, which makes it possible for users to train big data model locally. We design a two-phase solution to protect the security of users’ data and reduce the dimension of the items. Moreover, we optimize the proposed scheme by introducing a stabilization mechanism to decrease the scale of the perturbed gradients. Some experimental results are given with two real online datasets, MovieLens and LibimSeTi. The theoretical analysis and experimental results demonstrate that compared with other methods, the proposed scheme achieves a good performance in terms of security, accuracy, and efficiency.

Towards Practical and Privacy-Preserving Multi-Dimensional Range Query Over Cloud

It is undeniable that Internet of Things (IoT) in big data era can provide us with huge volumes of multi-dimensional data, transforming our society into a much more intelligent one. In order to fit for the multi-dimensional data processing in big data era, multi-dimensional range queries, especially over cloud platform, have received considerable attention in recent years. However, as the cloud server is not fully trustable, designing multi-dimensional range queries over encrypted data becomes a research trend, and many solutions have been proposed in the literature. Nevertheless, most existing solutions suffer from the leakage of the single-dimensional privacy, and such leakage would severely put the data at risk. Although a few existing works have addressed the problem of single-dimensional privacy, they are impractical in some real scenarios due to the issues of inefficiency, inaccuracy, and two-cloud-server requirement. Aiming at solving these issues, in this article, we propose a practical and privacy-preserving multi-dimensional range query (PRQ) scheme. Specifically, in our proposed PRQ scheme, we first index the multi-dimensional dataset with an R-tree and reduce R-tree based range queries to the problem of point intersection and range intersection. Then, by employing the lightweight matrix encryption technique, we design two novel algorithms for PRQ, i.e., multi-dimensional point intersection predicate encryption (PIPE) and multi-dimensional range intersection predicate encryption (RIPE), which can preserve the privacy of the proposed point intersection algorithm and range intersection algorithm, and further preserve the single-dimensional privacy of the proposed PRQ scheme. Detailed security analysis shows that our proposed PRQ scheme is indeed privacy-preserving. In addition, extensive simulations are conducted, and the results also demonstrate its efficiency.

A Lightweight and Privacy-Friendly Data Aggregation Scheme against Abnormal Data.

Abnormal electricity data, caused by electricity theft or meter failure, leads to the inaccuracy of aggregation results. These inaccurate results not only harm the interests of users but also affect the decision-making of the power system. However, the existing data aggregation schemes do not consider the impact of abnormal data. How to filter out abnormal data is a challenge. To solve this problem, in this study, we propose a lightweight and privacy-friendly data aggregation scheme against abnormal data, in which the valid data can correctly be aggregated but abnormal data will be filtered out during the aggregation process. This is more suitable for resource-limited smart meters, due to the adoption of lightweight matrix encryption. The automatic filtering of abnormal data without additional processes and the detection of abnormal data sources are where our protocol outperforms other schemes. Finally, a detailed security analysis shows that the proposed scheme can protect the privacy of users’ data. In addition, the results of extensive simulations demonstrate that the additional computation cost to filter the abnormal data is within the acceptable range, which shows that our proposed scheme is still very effective.

Ablation Mechanism and Tensile Progressive Failure of Carbon/Phenolic 2.5d Woven Composites with Dense and Lightweight Matrix

Ablation Mechanism and Tensile Progressive Failure of Carbon/Phenolic 2.5d Woven Composites with Dense and Lightweight Matrix

Transfer matrix based layered materials rendering

A statistical multi-lobe approach was recently introduced in order to efficiently handle layered materials rendering as an alternative to expensive general-purpose approaches. However, this approach poorly supports scattering volumes as the method does not account for back-scattering and resorts to single scattering approximations. In this paper, we address these limitations with an efficient solution based upon a transfer matrix approach which leverages the properties of the Henyey-Greenstein phase function. Under this formalism, each scattering component of the stack is described through a lightweight matrix, layering operations are reduced to simple matrix products and the statistics of each BSDF lobe accounting for multiple scattering effects are obtained through matrix operators. Based on this representation, we leverage the versatility of the transfer matrix approach to efficiently handle forward and backward scattering which occurs in arbitrary layered materials. The resulting model enables the reproduction of a wide range of layered structures embedding scattering volumes of arbitrary depth, in constant computation time and with low variance.

Compressive mechanical properties of low-cost, aluminium matrix syntactic foams

Metal matrix syntactic foams (MMSFs) are high-performance foams consisting of a light-weight matrix and a set of porous fillers. The obstacle against the wide-spreading of MMSFs is their high cost (raised by the fillers’ price). In this study, low-cost MMSFs have been developed and characterised in the structure – mechanical properties relationship aspect. The MMSFs were produced by low-pressure infiltration from the combination of two matrices (Al99.5, AlSi9MgMn) and three nominal diameters (4, 8 or 11 mm) light expanded clay agglomerate particles (LECAPs). The density of the MMSFs was 1.38–1.53 g.cm−3. The mechanical properties were characterised by compressive tests. The effects of the alloying and T6 heat treatment were evaluated. Exponential relationships were found between the LECAPS’ fracture force values and the strength and absorbed energy values. The produced MMSFs proved equal or higher properties than the top materials investigated in the literature. The produced MMSFs showed plastic collapse failure.

Properties of Lightweight Matrix according to Different Types of Alkali Stimulants

Recently, lightweight wall systems have been used mainly due to the appearance of flexible buildings, but EPS, which is flammable, is the main material. The damage caused by toxic gas in fire is recognized as a problem. NaOH, KOH and Ca(OH)2 were used as alkali stimulants and the properties of the matrix were evaluated according to the addition ratio of alkali stimulants. The addition of an alkali stimulant increases the pH and increases the alkali activity of the blast furnace slag, thereby changing the performance of the matrix. When NaOH and KOH are used as alkali stimulants, the density of the cured product is low and the incidence of the internal void of the cured product is high. When Ca(OH)2 is used as an alkali stimulant, it shows the best performance when measuring pH, setting time, and strength. This seems to be due to the ionization degree of the (OH) group. However, the incidence of voids was the lowest. When NaOH and KOH are used as alkali stimulants, the density of the cured product is low and the incidence of the internal void of the cured product is high. When Ca(OH)2 is used as an alkali stimulant, it shows the best performance when measuring pH, setting time, and strength. This seems to be due to the ionization degree of the (OH) group. However, the incidence of voids was the lowest.

Matrix-based key management scheme for IoT networks

The key management is the central element of network security. In fact, key distribution is necessary for securing applications in the context of Internet of Things (IoT). However, existing key management protocols are not directly applicable on IoT due, among other things, to severe and high resource constraints of some devices that make up the IoT network. Therefore, it is necessary that the proposed key management protocols takes in charge these features and constraints. Most existing solutions didn’t focus on optimizing, at the same time, all performance criteria, like communication, computation and storage. Some of them put special emphasis on minimizing one criteria but ignore the others. In this paper, we propose a new lightweight matrix based key management protocol for Iot network, which is not only flexible, scalable and resilient to many types of attacks, but also can reduce the communication, computation and storage overheads at constrained nodes side. The security properties like authentication, integrity and secrecy have been checked by using the formal verification tool AVISPA. Moreover, security and performance analysis show that our scheme protects user’s sensitive data from several types of attacks by achieving secure end-to-end communications, and optimizes the energy consumption, which is suitable for resource-limited networks.

Properties of Lightweight Matrix Using Industrial by-Products according to Mixing Ratio of NaOH and KOH

Background/Objectives:When producing 1 ton of cement, it produces 0.9 tons of carbon dioxide, so it is very important to reduce the use of cement or to find an alternative material.Methods/Statistical analysis: In order to replace cement which is frequently used to make lightweight cured products, blends of blast furnace slag, polysilicon and paper ash were used as binders. In order to stimulate the hardening of blast furnace slag, comparative analysis of characteristics of alkali stimulants was carried out by using KOH and NaOH as alkali stimulants.Findings: In order to improve the foaming performance for the production of lightweight Matrix, we used polysilicon and paper ash as well as blast furnace slag as one of industrial by - product a binder. KOH and NaOH were used as alkali stimulants. The experimental results are as follows.When alkali stimulants are used, the density decreases and the absorption rate increases. It is considered that the use of an alkali stimulant causes air bubbles to occur, resulting in a lower density and an increased absorption rate. The use of NaOH rather than KOH seems to result in better bubble generation. Strength was significantly decreased when alkali stimulants were used, but it was confirmed that the strength of NaOH was increased than that of KOH.Improvements/Applications: As a result of this study, we will fabricate a lightweight matrix that can be used as a prototype by using NaOH according to KS F 2701 standards.

A Review on Mechanical and Acoustic Emission Behavior of Basalt Fiber Reinforced Composites

Now a day’s eco-friendly natural fiber used as the reinforcement for the fabrication of the light weight, lower cost and biodegradable polymer matrix composites. One of such available natural reinforcement for the composite material is basalt fiber. The present paper gives a review on how the basalt fiber reinforced polymer matrix composite behave when they are adhesively, riveted and hybrid joined with other reinforcements such as aluminum, which is used for the particular or other applications and which joint gives better efficiency , suited for given application were discussed and the three joining techniques were investigated. Behavior of basalt fiber reinforced composites for the frequencies at which frequencies the failures like adhesive failure, light fiber tear, and mixed failure modes will occur. These three types of failure modes are investigated with the help of acoustic emission monitoring system.

Properties of Lightweight Composites Using Industry Wastes with NaOH Alkaline Activator

Lightweight concrete has been adopted to prefabricated elements such as facades, staircases and wall systems in housing projects. Many research have been carried out on production of lightweight panels without using ordinary portland cement. The objective of this experimental study was to develop construction materials applicable to lightweight wall system by using ground granulated blast furnace slag and paper ash, which are industrial by-products. Specifically, we carried out an experimental research on the properties of a lightweight matrix that could have application to lightweight wall systems without involving any use of Portland cement that emits massive amount of carbon dioxide (CO2) from chemical process and burning fuel; the major culprit behind global warming. In this study, we used NaOH alkaline activator to achieve the strength of a ground granulated blast furnace slag-based matrix without using general Portland cement. As a result, the mechanism was uncovered as to how NaOH alkaline activator led to the generation of hydrogen gas through reaction with the unreacted Si of paper ash. In addition, we found that construction materials applicable to lightweight wall systems could be manufactured by using ground granulated blast furnace slag and paper ash, industrial by-products.

Comparison of the Wear Properties of Polymer Composites Having CNT With and Without Glass Fiber Reinforcement

The adoption of light weight and high performance polymer matrix composites are needed for industries related to aerospace, automotive, consumer goods, etc. Polymer fiber reinforced composite material have very good desirable mechanical and thermal properties like low density, higher specific stiffness with high specific strength and a controlled co-efficient of thermal expansion with dimensional stability. The addition of carbon nanoparticle in these composites improved mechanical as well as wear properties of the material, which leads to more applications of these composites in various fields. In the present investigation carbon nanotube addition along with the glass fiber reinforced composite material was used as work material. The sliding wear tests were carried out on pin on disc wear tester. The tribological performance was studied by varying the applied load. The wear surfaces were analyzed by using scanning electron microscope, X-ray diffraction and energy-dispersive X-ray spectroscopy which are presented in detail.

Foaming Properties of Lightweight Matrix Based with Non-Reacted Si Blast Furnace Slag

Foaming Properties of Lightweight Matrix Based with Non-Reacted Si Blast Furnace Slag

DNSRadar: Outsourcing Malicious Domain Detection Based on Distributed Cache-Footprints

As the domain name system (DNS) plays a critical role in malicious services and number of networks, especially small enterprise networks and home networks that are generally and poorly managed, grows rapidly, it is highly desired to outsource the malicious domain detection service to a thirdparty system that can aggregate information from multiple vantage points to perform detection. To this end, we propose DNSRadar, a system that explores the coexistence of domain cache-footprints distributed in all networks that participate in the outsourcing service. Bootstrapping from a list of prelabeled malicious domains, DNSRadar leverages link analysis techniques to infer maliciousness likelihood of unknown domains based on coexistence information. As DNSRadar only uses the existence of an unknown domain in a network for detection, privacy concerns have been drastically reduced. Both MapReduce and lightweight matrix analysis techniques are employed to implement DNSRadar, making scalability as a built-in feature. Taking advantage of a large number of open recursive DNS servers, we have performed extensive evaluation at scale. Experimental results have demonstrated that DNSRadar can efficiently detect ~90% malicious domains given a low false positive rate of 1%. Of all these detected malicious domains, ~30% are on average 6 days earlier than public DNS reputation services, indicating DNSRadar's great early detection capability.

Concentrating immunoprotective phytoactive compounds from fruits and vegetables into shelf-stable protein-rich ingredients.

Co-delivery of edible proteins with health-protective fruit (muscadine grape) and vegetable (kale) phytoactive compounds was accomplished in a biofortified ingredient for use in convenient, portable food formulations. Polyphenolics were concentrated (10-42 mg/g range) in dry muscadine-protein matrices. Kale-fortified protein matrices also captured polyphenolics (8 mg/g), carotenoids (69 μg/g) and glucosinolates (7 μmol/g). Neither total phenolics nor glucosinolates were significantly diminished even after long term (6 months) storage at 4, 20, or 37 °C, whereas carotenoids degraded over time, particularly at higher temperatures. Dry biofortified phytoactive-protein ingredients allowed delivery of immunoprotective compounds from fruits and vegetables in a stable, lightweight matrix.

MCBS: Matrix Computation Based Simulator of NDN

This paper presents a lightweight matrix computation-based simulator of Named Data Networking (NDN). This simulator treats the experiment network as a whole. Matrix is used to describe network states, and matrix operation is used to simulate different network events. The simulator, just like Newtonian mechanics to some extend, once given the system initial state, including routing table, content distribution, and initial data requesting information of NDN network, can figure out all of the subsequent network state based on matrix computation. This simulator splits packet process into different events, such as interest generating, interest forwarding, cache or content hitting and transmitting, and turns them into matrix computation on the network scale. One of advantages of the simulator is convenient and user-friendly compared to CCNx Project and NS-3 based simulator. And they can provide similar simulation result. This simulatorcan works on different platform, including Linux, mac OSX and Windows. Computational complexity of the simulator depends on number of involved contents and nodes, which makes analysis between small group of nodes and contents very simple and fast.

Monolithic porous carbon prepared by Na2 CO3 templating as a substrate for a nickel hydroxide electrode

Monolithic porous carbon (MPC) was synthesized by a templating method using Na 2 CO 3 as template, novolac-type phenolic resin as carbon precursor and hexamethylenetetramine as hardening agent. The template, carbon precursor and hardening agent were mechanically mixed in a grinding machine, hardened at 150 °C, crushed into fine particles, compacted into a disc, carbonized at 800 °C and finally washed with deionized water to form MPC. MPC–Ni(OH) 2 electrodes were prepared by loading Ni(OH) 2 into the MPC by cathodic deposition. The MPC is hierarchically porous, has an electric conductivity of 20.40 S cm −1 and a specific surface area of 576 m 2 g −1 . Charge-discharge characterization of the MPC–Ni(OH) 2 electrodes shows that the specific capacities based on active material and the whole electrode are 230 mAh g −1 and 131 mAh g −1 , respectively. This suggests that the MPC is a promising lightweight matrix to host nickel hydroxide to achieve a high specific energy in nickel-based alkaline batteries. [New Carbon Materials 2013, 28(2): 115–120]

Applying a polyurea coating to high-performance organic cementitious materials

Polyurea is a polymeric material that can be used to provide environmental protection and structural enhancement. In this study, a low modulus polyurea coating, having high elongation and energy absorption capacities and a fast gel time, was sprayed under field conditions onto the surfaces of cementitious materials. Compression tests were conducted to establish the wet–dry performance of uncoated and circumferentially coated cylinders fabricated from a high-performance matrix constructed with Poly(vinyl butyral) (PVB) as the only aggregate. Results showed that the coating increased the compressive strength of specimens exposed to both fresh and sea water environments. Similar results were obtained when a lightweight matrix containing sand was subjected to the same sea water environment. Flexure tests were conducted on uncoated and fully encapsulated plates kept under normal operating conditions to establish the stress–strain behavior of these two matrices, as well as a PVB matrix with Poly(vinyl alcohol) (PVA) fibers added as reinforcement. Results showed that the addition of the fibers and the coating increased the ultimate flexural strength, decreased the stiffness, allowed the structure to sustain higher strains prior to failure, and increased the fracture toughness. Comparisons are made between the performance of lightweight and high-performance concretes.

Preparation and the Electrochemical Properties of Monolithic Porous Carbon as a Substrate for Nickel Hydroxide Electrode

Phenolic-resin-based monolithic porous carbon (MPC) with large pores of about 2 μm in diameter has been prepared and evaluated as a possible substrate for the nickel hydroxide electrode. It has been observed that the MPC is basically electrochemically stable in the voltage range in which the nickel hydroxide electrodes operate. The Ni(OH)2 materials are loaded into the MPC using cathodic electrodeposition from the nickel nitrate solutions. This is performed by pulsing square-wave electrodeposition at room temperature. The ohmic drop of the MPC-Ni(OH)2/NiOOH electrodes during the charge-discharge process is largely due to their relatively low conductivity. The initial charge-discharge characterization of the MPC-Ni(OH)2/NiOOH electrodes shows that the specific capacity of the electrode material (SCEM) reaches 115 mAh·g−1 in terms of the total electrode weight. The above mentioned value is considerably higher than that of state-of-the-art sintered Ni-Ni(OH)2/NiOOH electrodes. Thus, it can be suggested that the MPC is a promising lightweight matrix for the Ni(OH)2/NiOOH electrodes with a focus on acquiring high weight specific energy for application in nickel-based alkaline batteries.