COMBINATORIAL DESIGN APPROACHES FOR AUTOMATIC TEST GENERATION

The n-way combination testing is a specification-based testing criterion, which requires that for a system consisted of a few parameters, every combination of valid values of arbitrary n(n ≥ 2) parameters be covered by at least one test. This letter proposed two different test generation algorithms based on combinatorial design for the n-way coverage criterion. The automatic test generators are implemented and some valuable empirical results are obtained.     

Applying Hopfield neural network to QoS routing in communication network

The main goal of routing solutions is to satisfy the requirements of the Quality of Service （QoS） for every admitted connection as well as to achieve a global efficiency in resource utilization. In this paper proposes a solution based on Hopfield neural network （HNN） to deal with one of representative routing problems in uni-cast routing, i. e. the multi-constrained（MC） routing problem. Computer simulation shows that we can obtain the optimal path very rapidly with our new Lyapunov energy functions.     

Design and fabrication of sub-μs silicon-on-insulator thermo-optic 4×4 switch matrix

A rearrangeable nonblocking silicon-on-insulator-based thermo-optic 4x4 switch matrix with spot size converters （SSCs） and a new driving circuit are designed and fabricated. The introduction of a spot size converter （SSC） has decreased the insertion loss to less than 10dB and the new driving circuit has improved the response speed to less than l~s.     

Preparation of CdSe nanocrystals in organic system and electroluminescence characteristics of the devices

Semiconductor nanocrystals have attracted wideinter-estsinthe last fewyears because they have high lumi-nescence efficiency and size-tunable band gap character-istics .The semiconductor nanocrystals could be func-tionalized using various surfactants to ma…     

A multicast dynamic wavelength assignment algorithm based on matching degree

The wavelength assignment with multiple multicast requests in fixed routing WDM network is studied. A new multicast dynamic wavelength assignment algorithm is presented based on matching degree. First, the wavelength matching degree between available wavelengths and multicast routing trees is introduced into the algorithm. Then, the wave.length assignment is translated into the maximum weight matching in bipartite graph, and this matching problem is solved by using an extended Kuhn-Munkres algorithm. The simulation results prove that the overall optimal wavelength assignment scheme is obtained in polynomial time. At the same time, the proposed algorithm can reduce the connecting blocking probability and＂ improve the system resource utilization.     

Magnetic field sensor based on peanut-shape structure and multimode fiber

An all fiber magnetic field sensor with peanut-shape structure based on multimode fiber (MMF) is proposed and experimentally demonstrated. The sensing structure and magnetic fluid (MF) are both encapsulated in capillary, and the effective refractive index of MF is affected by surrounding magnetic field strength. The measurement of magnetic field is realized by observing the wavelength drift of interference peak. The transmission spectrum generated by Mach-Zehnder interferometer (MZI) includes core-core mode interference and core-cladding mode interference. Experimental results demonstrate that the core-cladding mode interference is sensitive to magnetic field, and the magnetic field sensitivity is 0.047 8 nm/mT. In addition, two kinds of interference dips are sensitive to temperature, and the sensitivities are 0.060 0 nm/°C and 0.052 6 nm/°C, respectively. So the simultaneous measurement of magnetic field strength and temperature can be achieved based on sensitivity matrix. This work has been supported by the National High Technology Research and Development Program of China (No.2013AA014200), the National Natural Science Foundation of China (No.11444001), and the Municipal Natural Science Foundation of Tianjin (No.14JCYBJC16500). E-mail:13821538563@163.com      

Periodical rocking long period gratings in PANDA fibers for high temperature and refractive index sensing

We report periodical rocking long period gratings (PR-LPGs) in PANDA fibers fabricated with CO2 laser. The PR-LPGs achieve very high coupling efficiency of 19 dB with 12 periods and a 3.5° twist angle in just one scanning cycle, which is much more effective than the conventional CO2 laser fabrication technique. This type of LPGs exhibits polarization-selective resonance dips which demonstrate different sensitivities to environmental parameters. The high temperature and external refractive index sensitivities are measured simultaneously, so it can be used as a wavelength-selective polarization filter and sensor. This work has been supported by the National Natural Science Foundation of China (No.61605168), the Natural Science Foundation of Hebei Province (No.F2016203392), the College and University Natural Science Foundation of Hebei Province (No.QN2016078), the Science and Technology Project of Qinhuangdao City (No.201601B050), and the Intramural Doctoral Foundation of Yanshan Universtiy (No.B1011). E-mail:jinwa@ysu.edu.cn      

Influence of reaction temperature on the formation process of ZnO quantum dots and the optical properties

ZnO quantum dots (QDs)with the sizes of 3.0-5.6 nm are synthesized by solution-phase method at different temperatures. We find that temperature has great influence on the size of ZnO QDs. The growth process is the most sensitive to temperature, and the process is well explained by Lifshitz-Slyozov-Wagner (LSW) model. By photoluminescence (PL) spectra of the quantum dots at different temperatures and reactive time, we come to a conclusion that ultraviolet emission is mainly due to surface defects, and the or...     

A novel soft reliability-based iterative majority-logic decoding algorithm with uniform quantization

In this paper, a novel soft reliability-based iterative majority-logic decoding algorithm with uniform quantization is proposed for regularly structured low density parity-check (LDPC) codes. A weighted measure is introduced for each check-sum of the parity-check matrix and a scaling factor is used to weaken the overestimation of extrinsic information. Furthermore, the updating process of the reliability measure takes advantage of turbo-like iterative decoding strategy. The main computational complexity of the proposed algorithm only includes logical and integer operations with the bit uniform quantization criterion. Simulation results show that the novel decoding algorithm can achieve excellent error-correction performance and a fast decoding convergence speed. This work has been supported by the National Natural Science Foundation of China (Nos.61472464, 61671091 and 61471075), the Natural Science Foundation of Chongqing Science and Technology Commission (No.cstc2015jcyjA0554), the Program for Innovation Team Building at Institutions of Higher Education in Chongqing (No.J2013-46), and the Undergraduate Science Research Training Project for Chongqing University of Posts and Telecommunications (No.A2016-61). E-mail:yuanjg@cqupt.edu.cn      

Low-loss fiber optic rotary joint using C-lens collimators

A low-loss fiber optic rotary joint （FORJ） has been designed by using two kinds of C-lens collimators. Its insertion loss and insertion loss variation due to rotation with single-mode fiber collimator is less than 1.76 dB and 0.43 dB respectively. The maximum insertion loss and coupling variation due to rotation with multi-mode fiber collimator is 1.71 dB and 0.29 dB, respectively. This kind of FORJ features low insertion loss, small coupling variation due to rotation and low cost.     

A flat microwave photonic filter based on M-Z modulator and fiber Bragg grating

A new multiple-taps and flat microwave photonic filter, which is composed of fiber Bragg grating, M-Z modulator and erbium-doped fiber, is put forward. The flat band-pass or flat band-stop response can be realized by adjusting the coupler＇s factor and the reflectivity of the fiber Bragg grating or the gain of the erbium-doped fiber. The free spectral range of the filter can be tuned by controlling the length of the erbium-doped fiber. The potential and feasibility of the proposed filtering structures have been demonstrated by simulation.     

Improvement of normalized throughput in WDM ＋ OCDMA system using optical hard-limiters

Recently,because of advantages of high-speed opticalprocessing and si mple network control ,the optical codedivision multiple access (OCDMA) has become a hotscheme in LAN and access network[1-5]. According tothe spreading mode, OCDMAcan be mainly dividedi…     

Design of photonic crystal fibers with anomalous dispersion

Photonic crystal fibers (PCFs) have attracted greatattentionin recent years due to their interesting proper-ties ,such as endless single-mode operation,unique dis-persion and nonlinear characteristics[1 ,2].It has been re-ported that PCFs offer a wide range of potential applica-tions ,such as 2Rregenerators ,optical parametric ampli-fiers ,dispersioncompensationandsuper-continuumgen-eration[3].Also called holey fibers or microstructure fi-bers ,PCFs are optical fibers possessing periodic a…     

A novel intrusion detection mode based on understandable neural network trees

Several data mining techniques such as Hidden Markov Model （HMM）, artificial neural network, statistical techniques and expert systems are used to model network packets in the field of intrusion detection. In this paper a novel intrusion detection mode based on understandable Neural Network Tree （NNTree） is presented. NNTree is a modular neural network with the overall structure being a Decision Tree （DT）, and each non-terminal node being an Expert Neural Network （ENN）. One crucial advantage of using NNTrees is that they keep the non-symbolic model ENN＇s capability of learning in changing environments. Another potential advantage of using NNTrees is that they are actually ＂gray boxes＂ as they can be interpreted easily if the number of inputs for each ENN is limited. We showed through experiments that the trained NNTree achieved a simple ENN at each non-terminal node as well as a satisfying recognition rate of the network packets dataset. We also compared the performance with that of a three-layer backpropagation neural network. Experimental results indicated that the NNTree based intrusion detection model achieved better performance than the neural network based intrusion detection model.     

Wavelength-shift detection system based on matching-FBG with enhanced temperature sensitivity

In this letter a fiber Bragg grating （FBG） interrogation system based on thermistance and matching-FBG of temperature sensitivity enhancement is proposed and demonstrated. According to the relationship between the center wavelength of the matching-FBG and the resistance value of the thermistance, the scheme interrogates the wavelength-shift by adjusting the matching-FBG＇s temperature and detecting the resistance value of the thermistance. In measure experiments, the results show that the precision of the proposed system is 0. 048 nm in a range of 9.4 nm.     

Global motion estimation from randomly selected motion vector groups and GM/LM based applications

Fast global motion estimation has been paid much attention in video compression and analysis. In this paper, a global motion estimation method is proposed by randomly selected motion vector groups in the compression domain directly. It is carried out by refining the centroid of the global motion parameters corresponding to the motion vector groups. Simulation results on different global motions show its effectiveness and robustness against noise and motion vector loss. Finally, two applications, namely the text occluded region recovery and the error concealment, are presented using the global motion/local motion information. Experimental results show the effectiveness of the proposed method. This work is supported in part by China National Natural Science Foundation (CNSF) under Project No.60572045, the Ministry of Education of China Ph. D. Program Foundation under Project No.20050698033, and by a Cooperation Project (2005.7- 2007.7) with Microsoft Research Asia.     

Transmission spectra of coated phase shifted long-period fiber gratings

The transmission spectrum of the coated phase-shifted long-pcriod fiber gratings （LPFCrs） with single and multiple phase shifts is analyzed by the coupled-mode theory and the transfer matrix method, and the influences of the film parameters on the spectral characteristics are also studied. It is shown that these parameters will affect the LPFG filtering characteristics. The loss peak of Wansmission spectrum decreases with the increase of film thickness, and the peak position shifts with the film refractive index. Compared with the non-coated phase-shifted LPFG, the coated one has the similar desirable filtering characteristics, and it has a flexible ability to adjust the transmission properties.     

Research on perfect dyadic binary sequence pair

In this paper, the perfect dyadic binary sequence pair with one-value dyadic correlation functions is presented. That is, the perfect dyadic binary sequence pair is a perfect discrete signal, for its dyadic relative function is δ-function. The transformation features and some existing admissibility conditions of perfect dyadic binary sequence pair are discussed, and the properties for this kind of code in Walsh transformation spectrum and weight spectrum are also analyzed. From above, It is found that the perfect dyadic binary sequence pair can easily differentiate from its dyadic shifting. So these good signals can used in engineering as synchronization code, multi-user code and so on.     

Green phosphorescent organic light-emitting devices based on different electron transport layers combining with fluorescent sub-monolayer

We report a small molecule host of 4,4(-N,N)-dicarbazole-biphenyl (CBP) doped with 8% tris(2-phenylpyridine) iridium (Irppy3) for use in efficient green phosphorescent organic light-emitting devices (PHOLEDs) combined with different electron transport layers of Alq and BAlq. The PHOLEDs exhibit maximum current efficiency and power efficiency of 19.8 cd/A and 6.21 lm/W, respectively. The high performance of such PHOLEDs is attributed to the better electron mobile ability of BAlq and sub-monolayer quinacridone (QAD) as carrier trapping layer and equal charge carrier mobilities of hole and electron to form the broad carrier recombination zone in the emitting layer, which can reduce the triplet-triplet annihilation and improve the efficiency of the device. #$TABThis work has been supported by the Major Project of Science and Technology Office of Fujian Province of China (No.2014H0042), the Natural Science Foundation of Fujian Province of China (No.2015J01664), the Project of Science and Technology Research of Quanzhou in Fujian Province of China (Nos.2013Z125 and 2014Z137), and the 2016 Annual National or Ministries Preparatory Research Foundation Project in Quanzhou Normal University (No.2016YYKJ21). E-mail:yanghuishan1697@163.com      

Real-time target recognition system simulation based on laser near-field detection

This paper constructs a simulation system of near-field laser imaging for 3D grid model of target, provides some methods for the key problems, such as the modeling of target and laser transceiver, the calculation of laser echo power, the imaging algorithms and so on. A target image library is established by a new imaging method in any rendezvous conditions. The four real-time recognition algorithms which are efficient and suitable for hardware implementation are presented at the conditions of the image incompleteness, intensive noise and arbitrary attitude of target. The experimental results show that all the four algorithms can independently recognize the target effectively and a better recognition effect is obtained by the integration of four algorithms.