Showing papers in "Journal of Shanghai University (english Edition) in 2007"
TL;DR: The structure and surface morphology of the SnS and SnS:In films were studied by X-ray diffraction (XRD) and scanning electron microscope (SEM) respectively Energy dispersive spectroscopy (EDS) showed the existence of In in the films.
Abstract: SnS and SnS:In films were deposited onto glass substrates by chemical bath technique The structure and surface morphology of the SnS:In films were studied by X-ray diffraction (XRD) and scanning electron microscope (SEM) respectively Energy dispersive spectroscopy (EDS) showed the existence of In in the films The undoped SnS film exhibited a rather high resistivity and InCl3 could reduce the resistivity of these films by two orders approximately The band gaps of the SnS and SnS:In films were evaluated from the optical transmission spectra
33 citations
TL;DR: A new method for recommending items using multiple agents collaborating each other to get recommendation for users by using MovieLens movie’s rating data.
Abstract: Automated collaborative filtering has become a popular technique for reducing information overload. We have developed a new method for recommending items using multiple agents. The agents were established by employing the fuzzy C-means clustering technique. We employ these agents collaborating each other to get recommendation for users. The results were evaluated by using MovieLens movie’s rating data. It is shown that the algorithm is an effective metrics in collaborative filtering.
29 citations
TL;DR: An approach to use run-time information to discover knowledge about software systems thus facilitating program comprehension is presented, and some dynamic metrics based on traces of the subject system execution are proposed.
Abstract: In this paper, an approach to use run-time information to discover knowledge about software systems thus facilitating program comprehension is presented. Some dynamic metrics based on traces of the subject system execution are proposed. A method of getting these dynamic metrics is introduced, in which instrumentation is implemented by using reflective mechanism based on an open compiler. The system run-time information is captured during the instrumented system running and is then analyzed to get these dynamic metrics. A case study is given to illustrate the use of these dynamic metrics, i.e., identifying critical components of the subject system. These critical components should be focus on user attentions in order to understand the subject system well.
23 citations
TL;DR: This article reviews some representative image hashing techniques proposed in the recent years, with emphases on how to meet the conflicting requirements of perceptual robustness and security, and introduces two image hashing approaches developed in the own research.
Abstract: The easy generation, storage, transmission and reproduction of digital images have caused serious abuse and security problems. Assurance of the rightful ownership, integrity, and authenticity is a major concern to the academia as well as the industry. On the other hand, efficient search of the huge amount of images has become a great challenge. Image hashing is a technique suitable for use in image authentication and content based image retrieval (CBIR). In this article, we review some representative image hashing techniques proposed in the recent years, with emphases on how to meet the conflicting requirements of perceptual robustness and security. Following a brief introduction to some earlier methods, we focus on a typical two-stage structure and some geometric-distortion resilient techniques. We then introduce two image hashing approaches developed in our own research, and reveal security problems in some existing methods due to the absence of secret keys in certain stage of the image feature extraction, or availability of a large quantity of images, keys, or the hash function to the adversary. More research efforts are needed in developing truly robust and secure image hashing techniques.
22 citations
TL;DR: Anisotropic conductive adhesives are now widely used in many applications and the reliability data and models have been developed to a large extent for anisotropicconductive adhesive adhesive in various applications as mentioned in this paper.
Abstract: Anisotropic conductive adhesive technology for electronics packaging and interconnect application has significantly been developed during the last few years. It is time to make a summary of what has been done in this field. The present paper reviews the technology development, especially from the reliability point of view. It is pointed out that anisotropic conductive adhesives are now widely used in many applications and the reliability data and models have been developed to a large extent for anisotropic conductive adhesives in various applications.
18 citations
TL;DR: In this paper, it was shown that the power domination number of an outerplanar graph with diameter two or a 2-connected innerplanar graphs with diameter three is precisely one.
Abstract: The problem of monitoring an electric power system by placing as few measurement devices in the system as possible is closely related to the well-known vertex covering and dominating set problems in graph theory. In this paper, it was shown that the power domination number of an outerplanar graph with the diameter two or a 2-connected outerplanar graph with the diameter three is precisely one. Upper bounds on the power domination number for a general planar graph with the diameter two or three were determined as an immediate consequences of results proven by Dorfling, et al. Also, an infinite family of outerplanar graphs with the diameter four having arbitrarily large power domination numbers were given.
16 citations
TL;DR: It is obtained that linear complexity and minimal polynomials of all Ding generalized cyclotomic sequences are independent of their orders, which makes it no more difficult in choosing proper p and q.
Abstract: Minimal polynomials and linear complexity of binary Ding generalized cyclotomic sequences of order 2 with the two-prime residue ring Z
pq are obtained by Bai in 2005. In this paper, we obtain linear complexity and minimal polynomials of all Ding generalized cyclotomic sequences. Our result shows that linear complexity of these sequences takes on the values p q and p q − 1 on our necessary and sufficient condition with probability 1/4 and the lower bound (p q − 1)/2 with probability 1/8. This shows that most of these sequences are good. We also obtained that linear complexity and minimal polynomials of these sequences are independent of their orders. This makes it no more difficult in choosing proper p and q.
16 citations
TL;DR: A special-purpose CAD/CAM software package, BliskCad/Cam is developed to reduce difficulties in CNC-EDM of the shrouded turbine blisks and can realize precision machining and reduce accessorial time remarkably.
Abstract: In this paper, a special-purpose CAD/CAM software package, BliskCad/Cam, based on a commercial CAD/CAM software Unigraphics is developed to reduce difficulties in CNC-EDM of the shrouded turbine blisks. The software package consists of five modules such as electrode design, path searching, and machining simulation module. Functions of BliskCad/Cam include parametrical reconstruction of 3-D model of the blisk, intelligent design of complex shaped electrode, automatic generation of NC codes, search of interference-free tool path for multi-axis NC-EDM and machining simulation, etc. Experimental verification is conducted by using BliskCad/Cam and the results show that it satisfies the requirements, and can realize precision machining and reduce accessorial time remarkably.
16 citations
TL;DR: In this article, a modification of the traditional interior wall paint was carried out by means of adding nano-TiO2 as a functional pigment, by regulating the dosage of dispersant, the nano-particles can be dispersed in paint homogeneously.
Abstract: The modification of the traditional interior wall paint was carried out by means of adding nano-TiO2 as a functional pigment. By regulating the dosage of dispersant, the nano-particles can be dispersed in paint homogeneously. With two aspects of experiments: dosage of nano-TiO2 and pigment volume concentration (PVC), the paint formulation can be optimized and its properties, such as hardness, scrub resistance, storage stability, contrast ratio and gloss can be improved. Finally an interior wall paint with high performance and air purification was prepared. Its character of formaldehyde degradation would be discussed in the next article.
15 citations
TL;DR: Experimental results indicate that the proposed scheme can achieve good visual quality with fairly large data capacity and can incorporate various coding methods such as matrix encoding to further improve the embedding performance.
Abstract: We present a novel scheme for embedding secret data into a binary image without introducing noticeable artifacts. Unlike some block-based methods, the proposed scheme encodes the secret bits directly into boundary pixels by checking each pixel of the cover image in a pseudo-random order for embedding eligibility. A set of rules ensures correct identification of data-carrying pixels in blind extraction. The proposed scheme does not generate isolated dots, and can incorporate various coding methods such as matrix encoding to further improve the embedding performance. It is shown that up to one fourth of the boundary pixels may be used to carry secret data. Experimental results indicate that the method can achieve good visual quality with fairly large data capacity.
14 citations
TL;DR: This paper introduces the advances of ultra- wideband (UWB) and super-wideband (SWB) planar antennas based on the printed monopole, microstrip slot and other planar antenna designs in the last decade.
Abstract: This paper introduces the advances of ultra-wideband (UWB) and super-wideband (SWB) planar antennas based on the printed monopole, microstrip slot and other planar antenna designs in the last decade. A brief history of the ultra-wideband antennas is first provided. Several types of planar antennas for UWB systems with band-notched designs are reviewed. Special SWB planar antenna designs with the bandwidth ratio greater than 10:1 including metal-plate and printed monopole antennas and tapered slot antennas are presented and compared.
TL;DR: In this article, the effect of rare earth elements on the morphologies and sizes of Si phases in the hypereutectic Al-Si alloys modified with P was investigated.
Abstract: The effect of rare earth (RE) elements on the morphologies and sizes of Si phases in the hypereutectic Al-Si alloys modified with P was investigated. The results show that the addition of La element to the hypereutectic Al-Si alloys can enhance the effect of P element on the modification of the primary Si phases. In the multiplex modification of RE-P, the primary Si phase is refiner and the shape of the eutectic Si is changed from long needle-like to short rod-like. Moreover, the agglomeration rate of the primary Si phase is slowed greatly. Even the melt is held for 6 h, the average size of the primary Si phase is still satisfied. The results analyzed by scanning electron microscope (SEM) indicate that La is richer at Al-Si interface than that in α-Al or primary Si phase. The higher the La content in the Al-Si interface, the smaller the primary Si phase.
TL;DR: The homological analysis shows that JSAD has high level of homology both in nucleotide sequence and in amino acid sequence to other plants SADs, and molecular modeling of JSAD indicates that its three-dimensional structure strongly resembled the crystal structure of RSAD.
Abstract: Using degenerate primers and RT-PCR, RACE techniques, a 1491 bp cDNA segment of stearoyl-acyl carrier protein desaturase (SAD) is cloned from developing seeds of Jatropha curcas L. The segment contains a 1191 bp of complete open reading frame (ORF). Analysis in the BLAST on NCBl shows that Jatropha curcas SAD (JSAD) gene encodes a protein precursor composed of a signal peptide of 33 amino acids and a mature peptide of 363 amino acids. The homological analysis shows that JSAD has high level of homology both in nucleotide sequence and in amino acid sequence to other plants SADs. The nucleotide and peptide identity of JSAD to Ricinus communis SAD (RSAD) is up to 89% and 96.2% respectively. Molecular modeling of JSAD indicates that its three-dimensional structure strongly resembled the crystal structure of RSAD.
TL;DR: An adaptive load balancing scheme is proposed to balance the load in ad hoc networks and can be applied in most on-demand routing protocols resulting in significant performance improvement.
Abstract: An adaptive load balancing scheme is proposed to balance the load in ad hoc networks. The new scheme can be applied in most on-demand routing protocols resulting in significant performance improvement. The proposed scheme is applied to the ad hoc on-demand distance vector (AODV) routing protocol. Simulation results show that the network load is balanced on the whole, and performance in packet loss rate, routing overhead and average end-to-end delay is also improved.
TL;DR: The new control strategy can minimize torque ripple, increase torque, and realize sensorless control for BLDC motor by using phase voltage as a control objective and making waveform of phase current approximately quasi-sinusoidal.
Abstract: In order to deal with torque pulsation problem caused by traditional control method for brushless DC (BLDC) motor and to achieve high precision and good stability, a novel control strategy is proposed. Compared with the traditional control scheme, by using phase voltage as a control objective and making waveform of phase current approximately quasi-sinusoidal, torque ripple of BLDC motor is reduced from the original 14% to 3.4%, while toque is increased by 3.8%. Furthermore, by detecting zero-crossings of back electromotive force (BEMF) with non-conducting phases, sensorless control is realized. The new control strategy is simple. It can minimize torque ripple, increase torque, and realize sensorless control for BLDC motor. Simulation and experiments show good performance of BLDC motor by using the new control method.
TL;DR: In this article, a fully polynomial time approximation scheme for the problem of scheduling n deteriorating jobs on two identical machines was worked out, and the result was generalized to the case of a fixed number of machines.
Abstract: In this paper, a parallel machine scheduling problem was considered, where the processing time of a job is a simple linear function of its starting time. The objective is to minimize makespan. A fully polynomial time approximation scheme for the problem of scheduling n deteriorating jobs on two identical machines was worked out. Furthermore, the result was generalized to the case of a fixed number of machines.
TL;DR: In this article, necessary and sufficient conditions for the existence of an antireflexive solution with respect to the generalized reflection matrix P to the system of complex matrix equations AX = B and XC = D were derived.
Abstract: We derive necessary and sufficient conditions for the existence and an expression of the (anti)reflexive solution with respect to the nontrivial generalized reflection matrix P to the system of complex matrix equations AX = B and XC = D. The explicit solutions of the approximation problem \(\mathop {\min }\limits_{X \in \phi } \) ‖X − E‖F was given, where E is a given complex matrix and ϕ is the set of all reflexive (or antireflexive) solutions of the system mentioned above, and ‖·‖ is the Frobenius norm. Furthermore, it was pointed that some results in a recent paper are special cases of this paper.
TL;DR: A laboratory-scale trickling biofilter column, filled with Raschig rings and inoculated with Pseudomonas putida was used to purify chlorobenzene contained waste gases, and addition of SDS to nutrient solution led to improvement of tricklingBiofilter purification performance.
Abstract: A laboratory-scale trickling biofilter column, filled with Raschig rings and inoculated with Pseudomonas putida (ATCC 1785) was used to purify chlorobenzene contained waste gases. Sodium dodecyl sulfonate (SDS) was used to enhance the performance of trickling biofilter. Purification performance of the trickling biofilter was examined for chlorobenzene inlet concentration of 1.20∼5.04 g/m3 at different EBRTs between 76∼153 s. Without SDS addition, with simultaneous increase in chlorobenzene inlet loading rate and gas flow rate, 100% removal efficiency was achieved at EBRT of 109 s and inlet loadings below 5120 mg/m3. Addition of SDS to nutrient solution led to improvement of trickling biofilter purification performance. By introducing 25 mg/L SDS, the removal efficiency was increased by 21% and elimination capacity up to 234 g/(m3·h) was achieved at chlorobenzene inlet loading of 241 g/(m3·h). Although SDS concentration experienced a low rate reduction after continuous nutrient solution recirculation, this result has little influence on trickling biofilter’s removal efficiency in monitoring period.
TL;DR: In this article, the precursors were prepared under the molar ratios of citric acid to the metal nitrate of 0.5, 1.0 and 1.5.
Abstract: BaFe12O19 powders with nanocrystalline sizes were produced by sol-gel auto-combustion method. The precursors were prepared under the molar ratios of citric acid to the metal nitrate of 0.5, 1.0 and 1.5. Appropriate ethylene diamine (C2H8N2) was added in order to adjust pH of 7. The ions distribution of citric acid at different pH explains the effect of citric acid in the starting solution. The XRD patterns of the as-burnt powders and annealing powders show different phases for different citric acid content. In addition, the lattice constants (a, c) derived from X-ray diffraction pattern were changed from 0.58881 nm to 0.58997 nm and 2.32057 nm to 2.32296 nm respectively. The data from VSM indicated that the powder with high citric acid content took on good magnetic properties. Pure single BaFe12O19 of the specific maximum magnetization M(1 T) ≈ 49.73 Am2/kg, the specific remanent magnetization M
r ≈ 30.77 Am2/kg and the coercive force H
c ≈ 467 kA/m was produced when the molar ratios of citric acid to the metal nitrate was 1.5.
TL;DR: Three dynamic performance models of DMFC under the influences of cell operating temperature, methanol concentration, and airflow rate are identified and established separately and modeling using fuzzy neural networks identification is satisfactory with high accuracy.
Abstract: This paper introduces the effects of cell operating temperature, methanol concentration and airflow rate, respectively, on the performance of direct methanol fuel cell (DMFC). A novel method based on fuzzy neural networks identification technique is proposed to establish the performance model of DMFC. Three dynamic performance models of DMFC under the influences of cell operating temperature, methanol concentration, and airflow rate are identified and established separately. Simulation results show that modeling using fuzzy neural networks identification is satisfactory with high accuracy. It is applicable to DMFC control systems.
TL;DR: In this article, the natural frequencies of an axially moving beam were determined by using the method of multiple scales, and the results obtained by the perturbation method were compared with those given with a numerical method and the comparison showed the correctness of the multiple-scale method if the velocity is rather small.
Abstract: The natural frequencies of an axially moving beam were determined by using the method of multiple scales. The method of second-order multiple scales could be directly applied to the governing equation if the axial motion of the beam is assumed to be small. It can be concluded that the natural frequencies affected by the axial motion are proportional to the square of the velocity of the axially moving beam. The results obtained by the perturbation method were compared with those given with a numerical method and the comparison shows the correctness of the multiple-scale method if the velocity is rather small.
TL;DR: This paper considers two semi-online parallel machine scheduling problems with linear deterioration processing time and investigates the worst-case ratio of the list (LS) algorithm, proving that all the ratios are tight.
Abstract: The combination of online or semi-online with deterioration jobs has never been researched in scheduling problems. In this paper, two semi-online parallel machine scheduling problems with linear deterioration processing time are considered. In the first problem, it is assumed that the deterioration rates of jobs are known in an interval, that is, bj ∊ [0, α], where 0 < α ⩽ 1 and bj denotes the linear deterioration rate. In the second problem, it is assumed that the largest deterioration rate of jobs is known in advance, that is, \(b_{\max } = \mathop {\max }\limits_{1 \leqslant j \leqslant n} \{ b_j \} \). For each of the two problems, a heuristic MBLS algorithm is worked out and its worst-case ratio is analyzed. At the same time, the worst-case ratio of the list (LS) algorithm is investigated and it is proved that all the ratios are tight.
TL;DR: Three types of immobilized beads had different capabilities for removing xylene and life-spans and one has a poorer intrinsic drawback in volatile organic compounds (VOCs) removal due to the existence of excess mass transfer resistance.
Abstract: The Bacillus firmus was immobilized into Ca-alginate beads according to the different initial biomass concentration, calcification time and activation time. Three types of immobilized Bacillus firmus beads were packed respectively in trickling biofilter to purify xylene contained waste gases, and the performance of immobilized-cell biofilter was compared with traditional biofilm attached biofilter packed with two types of ceramic pellets. The results showed that three types of immobilized beads had different capabilities for removing xylene and life-spans. Higher initial biomass in immobilized beads resulted in better performance but shorter life-span. Activation process can remarkably enhance the activity of bacteria, and the removal efficiency of xylene can substantially be improved. Calcification time had influence on life-span of immobilized beads. Without acclimation, the cell-entrapped biofilter can obtain the maximum elimination capacity of 92.4 g/(m3·h). However, compared with biofilm attached biofilter, it has a poorer intrinsic drawback in volatile organic compounds (VOCs) removal due to the existence of excess mass transfer resistance.
TL;DR: In this paper, the authors present a survey of recent progress on the topic of dominating functions in graph theory, including the definition of star dominating functions and edge dominating functions of graphs with integer values.
Abstract: For an arbitrary subset \(\mathcal{P}\) of the reals, a function f: V → \(\mathcal{P}\) is defined to be a \(\mathcal{P}\)-dominating function of a graph G = (V,E) if the sum of its function values over any closed neighbourhood is at least 1. That is, for every υ ∊ V, f(N[υ]) ≥ 1. The definition of total \(\mathcal{P}\)-dominating function is obtained by simply changing ‘closed’ neighborhood N[υ] in the definition of \(\mathcal{P}\)-dominating function to ‘open’ neighborhood N(υ). The (total) \(\mathcal{P}\)-domination number of a graph G is defined to be the infimum of weight w(f) = \(\sum\limits_{v \in V} {f(v)} \) taken over all (total) \(\mathcal{P}\)-dominating function f. Similarly, the \(\mathcal{P}\)-edge and \(\mathcal{P}\)-star dominating functions can be defined. In this paper we survey some recent progress on the topic of dominating functions in graph theory. Especially, we are interested in \(\mathcal{P}\)-, \(\mathcal{P}\)-edge and \(\mathcal{P}\)-star dominating functions of graphs with integer values.
TL;DR: The results showed that the Community Bareau of Reference (BCR) extraction can be utilized as an additional tool with the acid volatile sulfide (AVS) method for assessing the potential bioavailability and toxicity of metals in sediments as discussed by the authors.
Abstract: Nine elements (As, Cd, Cr, Cu, Fe, Mn, Ni, Pb, Zn) in sediment samples at 7 sites (Site 1–7) from Suzhou Creek in Shanghai were analyzed with the Community Bareau of Reference (BCR) (sequential extraction (SE)) protocol and simultaneously extracted metals (SEM)/acid volatile sulfide (AVS) procedure to assess the metal bioavailability and toxicology in this area. The results showed that the BCR extraction can be utilized as an additional tool with the AVS method for assessing the potential bioavailability and toxicity of metals in sediments. Pollution from S5 (Site 5) was more severe than from other sites, especially Pb, Cu and Zn. Among all the sites, more than 80% of the total concentration of Fe existed in the residual fraction, As, Cr, Mn also dominated in the residual fraction (more than 50%). While Cd, Ni and Zn (more than 35%) were mainly in the non-stable phase. Cu had a strong affinity with oxidizable phase and Pb varied from site to site. The SEM/AVS ratio was less than one in these sediments and results implied that the majority of Zn and Ni (> 40%) were bound to AVS. In contrast, Pb, Cu and Cd were little bound to AVS due to their low ration of SEM-Pb, Cu, Cd to corresponding total concentration and relatively high porewater concentration.
TL;DR: In this article, a global quasi-minimal residual (QMR) method was presented for solving the Sylvester equations, and the results showed that the global QMR method is less time-consuming than the global GMRES (generalized minimal residual) and block GMRES methods in some cases.
Abstract: In this paper, a global quasi-minimal residual (QMR) method was presented for solving the Sylvester equations. Some properties were investigated with a new matrix product for the global QMR method. Numerical results with the global QMR and GMRES methods compared with the block GMRES method were given. The results show that the global QMR method is less time-consuming than the global GMRES (generalized minimal residual) and block GMRES methods in some cases.
TL;DR: In this article, a serial synchronous scanning mode in flat panel display (FPD) was proposed by adding a latch buffer between the serializer and the driving buffer to reduce the brightness loss and improve transmission performance.
Abstract: This paper presents a serial synchronous scanning mode in flat panel display (FPD) by adding a latch buffer between the serializer and the driving buffer Comparing with conventional techniques, the proposed structure can efficiently reduce the brightness loss and improve the transmission performance Theoretical analysis and experimental results show that the ratio between the lightest weight display time and the relative transmission time is a tradeoff between brightness loss and transmission efficiency
TL;DR: In this article, the normal impingement process of two water droplets upon a thin film on the solid surface was numerically investigated based on the finite volume solution of the Navier-Stokes (N-S) equations combined with the volume of fluid method (VOF).
Abstract: The normal impingement process of two water droplets upon a thin film on the solid surface was numerically investigated. The numerical treatment was based on the finite volume solution of the Navier-Stokes (N-S) equations combined with the volume of fluid method (VOF). Physically reasonable results for the process of two droplets impacting on the thin film were obtained. The effects of the droplet velocity, the film thickness and the spacing between the two droplets on the splash and spread process of the impact were examined.
TL;DR: A new algorithm is presented by using the ant colony algorithm based on genetic method (ACG) to solve the continuous optimization problem by updating the trail information and a diffusion function is used to achieve the diffuseness of trail information.
Abstract: A new algorithm is presented by using the ant colony algorithm based on genetic method (ACG) to solve the continuous optimization problem. Each component has a seed set. The seed in the set has the value of component, trail information and fitness. The ant chooses a seed from the seed set with the possibility determined by trail information and fitness of the seed. The genetic method is used to form new solutions from the solutions got by the ants. Best solutions are selected to update the seeds in the sets and trail information of the seeds. In updating the trail information, a diffusion function is used to achieve the diffuseness of trail information. The new algorithm is tested with 8 different benchmark functions.
TL;DR: In this paper, a new method named as the gradually descent method was proposed to solve the discrete global optimization problem with the aid of an auxiliary function, which enables to convert the problem of finding one discrete minimizer of the objective function to that of finding another at each cycle.
Abstract: In this paper, a new method named as the gradually descent method was proposed to solve the discrete global optimization problem With the aid of an auxiliary function, this method enables to convert the problem of finding one discrete minimizer of the objective function f to that of finding another at each cycle The auxiliary function can ensure that a point, except a prescribed point, is not its integer stationary point if the value of objective function at the point is greater than the scalar which is chosen properly This property leads to a better minimizer of f found more easily by some classical local search methods The computational results show that this algorithm is quite efficient and reliable for solving nonlinear integer programming problems