JackHare: a framework for SQL to NoSQL translation using MapReduce

As data exploration has increased rapidly in recent years, the datastore and data processing are getting more and more attention in extracting important information. To find a scalable solution to process the large-scale data is a critical issue in either the relational database system or the emerging NoSQL database. With the inherent scalability and fault tolerance of Hadoop, MapReduce is attractive to process the massive data in parallel. Most of previous researches focus on developing the SQL or SQL-like queries translator with the Hadoop distributed file system. However, it could be difficult to update data frequently in such file system. Therefore, we need a flexible datastore as HBase not only to place the data over a scale-out storage system, but also to manipulate the changeable data in a transparent way. However, the HBase interface is not friendly enough for most users. A GUI composed of SQL client application and database connection to HBase will ease the learning curve. In this paper, we propose the JackHare framework with SQL query compiler, JDBC driver and a systematical method using MapReduce framework for processing the unstructured data in HBase. After importing the JDBC driver to a SQL client GUI, we can exploit the HBase as the underlying datastore to execute the ANSI-SQL queries. Experimental results show that our approaches can perform well with efficiency and scalability.     

High-power broad-area InGaNAs/GaAs quantum-well lasers in the 1200 nm range

High-power broad-area InGaNAs/GaAs quantum-well (QW) edge-emitting lasers on GaAs substrates in the 1200 nm range are reported. The epitaxial layers of the InGaNAs/GaAs QW laser wafers were grown on n⁺-GaAs substrates by using metal-organic chemical vapor deposition (MOCVD). The thickness of the InGaNAs/GaAs QW layers is 70 Å/1200 Å. The indium content (x) of the In_xGa_1−xN_yAs_1−y QW layers is estimated to be 0.35-0.36, while the nitrogen content (y) is estimated to be 0.006-0.009. More indium content (In) and nitrogen content (N) in the InGaNAs QW layer enables the laser emission up to 1300 nm range. The epitaxial layer quality, however, is limited by the strain in the grown layer. The devices were made with different ridge widths from 5 to 50 μm. A very low threshold current density (J_th) of 80 A/cm² has been obtained for the 50 μm × 500 μm LD. A number of InGaNAs/GaAs epi-wafers were made into broad-area LDs. A maximum output power of 95 mW was measured for the broad-area InGaNAs/GaAs QW LDs. The variations in the output powers of the broad-area LDs are mainly due to strain-induced defects the InGaNAs QW layers.     

Performance Evaluation of Mobility Anchor Point with Guard Load Reservation in Hierarchical Mobile IPv6

Hierarchical mobile IPv6(HMIPv6)introduces a mobility anchor point to reduce the signaling overhead and handoff latency. In this paper, we apply the matrix-analytical approach to explore the performance measures of the ongoing mobile nodes(MNs) drop and new MNs block probabilities of mobility anchor point with a guard bandwidth reservation scheme. We apply the Markovian arrival process(MAP)to model ongoing MNs and new MNs. Five related performance measures are derived, including the long-term new MN block and ongoing MN drop probabilities, and the three short-term measures of average length of a block period and a non-block period,as well as the conditional ongoing MN drop probability during a block period. These performance measures greatly assist the guard bandwidth reservation mechanism in determining a proper threshold guard bandwidth. The results presented in this paper can provide guidelines for designing adaptive algorithms to adjust the threshold in the guard bandwidth reservation scheme.     

High performance and high reliability of 1.55-μmcurrent-blocking grating complex-coupled DFB lasers

We report the high performance and high reliability of the 1.55 μm current-blocking grating complex-coupled InGaAsP strained distributed-feedback MQW lasers. Small variation in slope efficiency, high characteristic temperature, and high side mode suppression ratio have been achieved over a wide temperature range of 20°C-90°C. From the accelerated aging test, the median life at 25°C and 5 mW is estimated to be longer than 50 years     

A novel approach for multistage inference fuzzy control

This paper presents a methodology to the design of a multistage inference fuzzy controller in which the consequence in an inference stage is passed to the next stage as fact, and so forth. A new general method which is based on a performance index of the control system is used to generate fuzzy rule bases for the multistage inference. This proposed method can reduce the design cycle time. In order to reduce the computation time, a method for precomputing the match-degrees of fuzzy values is adopted. Thus, the number of operations that must be carried out at execution time can be significantly reduced. The new method has been applied to two applications, a two-trailer-and-truck system and a three-trailer-and-truck system. The simulation studies showed that the proposed method is feasible.     

High Input Impedance Voltage-Mode Universal Biquadratic Filter with One Input and Five Outputs Using Current Conveyors

A new high input impedance voltage-mode universal biquadratic filter with one input terminal and five output terminals is presented. The proposed circuit uses three differential voltage current conveyors (DVCCs), four resistors, and two grounded capacitors. The proposed circuit can realize all the standard filter functions—lowpass, bandpass, highpass, notch, and allpass—simultaneously, without changing the passive elements. The proposed circuit enjoys the features of high input impedance, orthogonal control of resonance angular frequency and quality factor, use of only grounded capacitors, and low active and passive sensitivities.     

MOCVD growth of strained multiple quantum well structure for 1.3 μm InAsP/InP laser diodes

In this article, we describe the growth and characterization for 1.3 μm InAsP/InP strained multiple quantum well (SMQW) laser diodes (LDs) with separate confinement heterostructure grown at 580°C by metalorganic chemical vapor deposition. The grown strained single quantum well (SSQW) stack and strained multiple quantum well (SMQW) structures are characterized using double-crystal X-ray diffraction and photoluminescence (PL) to confirm the structural and optical qualities for practical device applications. The InAsP/InP SSQW stack grown at 580°C appears to be extremely abrupt, uniform, free of misfit dislocations and narrow PL half width. Although the InAsP/InP SMQWs grown at 580°C maintain its structural integrity throughout the deposition sequence, the slightly broader PL half width for InAsP/InP SMQW structure is attributed to the dislocations resulted from a large net strain. Laser emission can be achieved by using the InAsP/InP SMQWs and the lasing wavelength is in a good agreement with our designed structure. The experimental data of broad-area and ridge waveguide LDs are described in detail.     

Influences of Web interactivity and social identity and bonds on the quality of online discussion in a virtual community

People participate in virtual communities (VCs) for knowledge sharing or social interaction. However, most studies of VCs have focused on elucidating knowledge sharing rather than predicting virtual social interactions. This study considers “quality of online discussion” an appropriate metric for assessing group-level outcomes of virtual social interactions, and thus for predicting member willingness to sustain an ongoing relationship with a virtual community (VC). This study develops a research model, grounded in Web interactivity, social identity and social bond theories, for predicting the quality of online discussion in terms of cognitive and social influences. Empirical results from an online survey of a VC verify distinct direct and indirect social influences (perceived internalization bonds and perceived identification bonds) and cognitive influences (perceived communication and perceived control). Implications for academics and practitioners are also discussed.     

Combining fuzzy weight average with fuzzy inference system for material substitution selection in electric industry

Material selection is a very important issue for an electronics company as it includes many qualitative or quantification factors. The material selection problem is associated with design and manufacturing problems which have been widely investigated. This study develops a hybrid fuzzy decision-making model which combines the fuzzy weight average (FWA) with the fuzzy inference system (FIS) for material substitution selection in the electronics industry. FWA is employed to select a substitute material in an uncertain environment, while FIS is used for reasoning purposes. FWA with α-cuts arithmetic (FWA_α-cut) is a popularly technology in decision-making problems. However, FWA_α-cut may result in the following unanticipated situations: (1) unclear decision situations; (2) undecided results expressed by fuzzy membership functions; and (3) high computational complexity. Therefore, a fuzzy weight average with the weakest t-norm (FWA_Tω) is designed as an alternative method for group decision making. In contrast to traditional FWA methods, FWA_Tω obtains more visible fuzzy results for decision makers with lower computational complexity, and can provide exacter estimation by the weakest t-norm operations in uncertain environment. Thus, the proposed hybrid fuzzy decision-making model imitates an expert’s experiences and can estimate substitution purchasing in various statuses. A real material substitution selection case is employed to examine the feasibility of the proposed model; experimental results reveal that the proposed model performs better than the traditional FWA model in coping with material substitution selection problems.