A Novel Three-Point Modulation Technique for Fractional-N Frequency Synthesizer Applications

This paper presents a novel three-point modulation technique for fractional-N frequency synthesizer applications. Convention modulated fractional-N frequency synthesizers suffer from quantization noise, which degrades not only the phase noise performance but also the modulation quality. To solve this problem, this work proposes a three-point modulation technique, which not only cancels the quantization noise, but also markedly boosts the channel switching speed. Measurements reveal that the implemented 2.4 GHz fractional-N frequency synthesizer using three-point modulation can achieve a 2.5 Mbps GFSK data rate with an FSK error rate of only 1.4 %. The phase noise is approximately -98 dBc/Hz at a frequency offset of 100 kHz. The channel switching time is only 1.1 μs with a frequency step of 80 MHz. Comparing with conventional two-point modulation, the proposed three-point modulation greatly improves the FSK error rate, phase noise and channel switching time by about 10 %, 30 dB and 126 μs, respectively

A Study of Application-awareness in Software-defined Data Center Networks

A data center (DC) has been a fundamental infrastructure for academia and industry for many years. Applications in DC have diverse requirements on communication. There are huge demands on data center network (DCN) control frameworks (CFs) for coordinating communication traffic. Simultaneously satisfying all demands is difficult and inefficient using existing traditional network devices and protocols. Recently, the agile software-defined Networking (SDN) is introduced to DCN for speeding up the development of the DCNCF. Application-awareness preserves the application semantics including the collective goals of communications. Previous works have illustrated that application-aware DCNCFs can much more efficiently allocate network resources by explicitly considering applications needs. A transfer application task level application-aware software-defined DCNCF (SDDCNCF) for OpenFlow software-defined DCN (SDDCN) for big data exchange is designed. The SDDCNCF achieves application-aware load balancing, short average transfer application task completion time, and high link utilization. The SDDCNCF is immediately deployable on SDDCN which consists of OpenFlow 1.3 switches. The Big Data Research Integration with Cyberinfrastructure for LSU (BIC-LSU) project adopts the SDDCNCF to construct a 40Gb/s high-speed storage area network to efficiently transfer big data for accelerating big data related researches at Louisiana State University. On the basis of the success of BIC-LSU, a coflow level application-aware SD- DCNCF for OpenFlow-based storage area networks, MinCOF, is designed. MinCOF incorporates all desirable features of existing coflow scheduling and routing frame- works and requires minimal changes on hosts. To avoid the architectural limitation of the OpenFlow SDN implementation, a coflow level application-aware SDDCNCF using fast packet processing library, Coflourish, is designed. Coflourish exploits congestion feedback assistances from SDN switches in the DCN to schedule coflows and can smoothly co-exist with arbitrary applications in a shared DCN. Coflourish is implemented using the fast packet processing library on an SDN switch, Open vSwitch with DPDK. Simulation and experiment results indicate that Coflourish effectively shortens average application completion time

Combining WMAP and SDSS Quasar Data on Reionization Constrains Cosmological Parameters and the Star Formation Efficiency

We present constraints on cosmological and star formation parameters based on combining observations of the Wilkinson Microwave Anisotropy Probe (WMAP) and high-redshift quasars from the Sloan Digital Sky Survey (SDSS). We use a semi-analytic model for reionization (Chiu and Ostriker 2000) that takes into account a number of important physical processes both within collapsing halos and in the intergalactic medium. Assuming that the efficiency of producing UV photons per baryon is constant, we derive a constraint of the form sigma_8 Omega_0^0.5~0.33 in a flat, Lambda-dominated universe with h=0.72, n=0.99, and Omega_b h^2=0.024. However, the calculated optical depth to electron scattering of tau_es~0.06 is well below the value found by WMAP of 0.17+/-(0.04~0.07) (Spergel et al 2003). Since the WMAP constraints on tau_es are somewhat degenerate with the value of the spectral index n, we then permit the primordial spectral index n to float and fix Omega_0 h^2=0.14, while normalizing the power spectrum using WMAP. In addition, we allow the UV-efficiency to have time-dependence. Combining the WMAP constraints with the quasar transmission data, our analysis then favors a model with tau_es=0.11^{+0.02}_{-0.03}, n=0.96^{+0.02}_{-0.03}$, implying sigma_8=0.83^{+0.03}_{-0.05} (95% confidence), and an effective UV-efficiency that was at least ~10x greater at z >> 6. These results indicate that the quasar and WMAP observations are consistent. If future observations confirm an optical depth to electron scattering tau_es~0.1, then it would appear that no more "exotic" sources of UV-photons, such as mini-quasars or AGNs, are necessary; but our analysis indicates that a determination of tau_es>~0.17 would require a more radical solution.Comment: 31 pages, 7 figures, 5 table

The effect of focused and unfocused indirect written corrective feedback on EFL learners\u27 accuracy in new pieces of writing

© 2015 Elsevier Ltd. The study examined the effectiveness of focused as opposed to unfocused written corrective feedback (WCF) on the accuracy of weak verbs and the total accuracy of all structures in new pieces of writing. Undertaken in a Taiwanese college context, the design of the study was quasi-experimental, comprising a pre-test, treatment, immediate post-test and delayed post-test. Three writing tasks were used for the tests and two different types of WCF represented the treatment: focused indirect WCF and unfocused indirect WCF. A control group received no WCF. The findings for the analysis of weak verb accuracy and total accuracy were remarkably similar. In both cases, parametric tests demonstrated the focused and unfocused indirect WCF groups not only outperformed the control groups in the immediate post-test but also in the delayed post-test. It is suggested that learners in both the focused indirect WCF group and the unfocused indirect WCF group were unable to notice the target structure or notice it with metalinguistic understanding following a single episode of WCF; instead, the indirect WCF likely served as a signal for the learners to push their output in their overall accuracy when writing new pieces of writing in the post-tests

Exploring Online Double Deviation Effect from Psychological Contract Violation, Emotion, and Power Perspectives

Service recovery is a critical moment of truth in retaining customers and reinforcing customer relationships, and has been considered as an “Achilles\u27 heel” in online marketplaces. Poor service recoveries exacerbate the negative effects of the failure, producing a “double deviation” effect. The double deviation effect may arise from the seller’s power misuse and then dissolve the buyer-seller relationship (e.g., violate consumer psychological contract), elicit consumer negative emotions which lead to customer coping behaviors. This study links the theories of psychological contract violation (PCV), emotion, and coping from the power perspective to investigate the double deviation scenario in online auction marketplaces. Two moderators (perceived power and perceived consumer empowerment) are considered in our proposed model. Data collected from 190 consumers of one auction website provide support for the proposed model. The results shed light on what constitutes the determinants of consumer judgments while facing double deviation scenario and how consumers react to and cope with it in online marketplaces. Finally, implications and limitations are discussed in the last part of this paper. Available at: https://aisel.aisnet.org/pajais/vol6/iss1/4

One plus one more than two : university-community partnerships for elderly : an interdisciplinary service-learning project

Faculties at Taipei Medical University developed an interdisciplinary courses cluster which consists of Chinese History, Nutrition, Elderly Activity Design, and Physical Examination. In this course cluster, faculties, students, teaching assistant, and NPO/community members serve the same elderly over two years by providing health related care in accordance with the courses objectives. In this project, not only students\u27 soft abilities, such as problem-solving skills, team work abilities, and communication abilities, are improved, but also develop some pilot devices for the elderly, such as remote health examination and instant soft meal. The paper will describe this model of interdisciplinary service-learning in health professions education, explores common experiences and themes across courses, and identifies key components for success

Blog Advertising Effectiveness – An Ad Endorser Perspective

Many consumers routinely gather product information and appraisals via the Internet before making purchase decisions. For them, blogs are an important information source. Therefore, enterprises have begun using blogs as a new and effective instrument of product marketing. However, selecting the blog type that optimizes advertising effectiveness is now an important issue in corporate advertising. This study classifies blogs into three types (celebrity blog, expert blog, and typical consumer blog) and defines product type (experience product and search product) and brand awareness (high and low) as two product constructs. The aim is to help enterprises evaluate the type and brand awareness of a product to be promoted and to select the blog type that maximizes advertising effectiveness (perceived risk, ad attitude, brand attitude, and purchase intention) in diffusing product information. A quasi-experiment design was adopted, and twelve experimental contexts were designed. A valid sample of over 2,000 responses was collected to study between-group differences in advertising effectiveness. The analytical results showed between-group difference in advertising effectiveness, which indicated that blog advertising effectiveness varies with different combinations of product constructs and blog types