Theory and design of mixed lumped-distributed cross-coupled filters with applications to linear phase shifter and tunable filters

Using cross-coupled networks of a new concept, transmission zeros were efficiently located in the complex frequency-domain. With this approach, the group delay and attenuation slope of the circuit network can be controlled to get both sharp rejection characteristics and linear phase slopes. In order to achieve this performance, various types of combline filters are suggested. Various simulation tools (commercial linear circuit and E-M simulators), as well as the developed pole-zero locator program, were used to design a new class of cross-coupled networks. In particular, the polezero locator program can be used to extract an equivalent circuit of the topology that is established from ether EM-simulated data or measured data. A new cross-coupled quasi-elliptic combline bandpass filter is presented, borrowing the distributed implementation of the capacitance (a top surface metalized dielectric block added as an applique to the top of the circuit), which was conventionally used without metalization to enhance the directivity of the microstrip couplers. The required cross coupling value was achieved by changing the substrate thickness, dielectric constant and area of the top surface metallization of the dielectric block. Effectively, an inhomogeneous transmission line was used to achieve source-load direct crosscoupling with at least one additional transmission zero. The first application presented, is a new type of reflection-type analog phase shifter using tunable short-terminated combline filters (STCL). An asymptotically approached 360-degree total phase shift is obtained, with a large linear range and an insertion loss of less than -1.5 dB over the full phase shift range at 5 GHz. The second approach presented, which is a new concept, is a tunable finite-transmission-zero filter, taking advantage of the unavoidable frequency dependence of each coupling. In order to obtain such a performance, ferroelectric or ferromagnetic stacked substrates are suggested for tuning the extra transmission zeros as well as the center frequency

Understanding Post-adoption Usage of Mobile Data Services: The Role of Supplier-side Variables

This study investigates factors that affect usage changes in mobile data services (MDS). First, we conducted an exploratory study based on 378 survey responses to learn about important decision factors of MDS usage. It revealed a discrepancy between the forces influencing usage increase and those of usage decrease. Based on the findings from the exploratory study and Hertzberg’s two-factor theory, we postulated information quality as the motivator and system quality as the de-motivator of MDS usage. Then, we undertook a confirmative study on the respective roles of these factors in encouraging and discouraging the usage of MDS. We proposed a research model and empirically tested our hypotheses with partial least square (PLS) analysis based on 478 responses from MDS users. Information quality (as a motivator) was positively associated with MDS usage increase, but system quality (as a de-motivator) was not. Also, system quality was negatively associated with usage decrease, but information quality was not. Last, their association was partially moderated by the type of motivation for using MDS. Information quality had a stronger influence on MDS usage increase when the main motive was utilitarian rather than hedonic

What Makes Usage of Mobile Data Service Increase or Decrease: Perspective of Two-Factor Theory

This study is to investigate factors that affect usage change in mobile data service (MDS). The central claim of this paper is that influencing forces of usage increase in MDS are different from those of usage decrease. We propose that information quality as the motivator (forces of usage increase) and system quality as the de-motivator (forces of usage decrease) of MDS. A research model is proposed and subsequent hypotheses are empirically tested with partial least square (PLS) based on 478 responses from the users of mobile data service. We have found that information quality (as a motivator) is positively associated with usage increase in mobile data service, but system quality (as a de-motivator) is not. Also, system quality is negatively associated with usage decrease, but information quality is not. Despite the recognized limitations, our study highlights the potential value of the two-factor theory in explaining user behaviors associated with mobile data services

Distribution of magnetic domain pinning fields in GaMnAs ferromagnetic films

Using the angular dependence of the planar Hall effect in GaMnAs ferromagnetic films, we were able to determine the distribution of magnetic domain pinning fields in this material. Interestingly, there is a major difference between the pinning field distribution in as-grown and in annealed films, the former showing a strikingly narrower distribution than the latter. This conspicuous difference can be attributed to the degree of non-uniformity of magnetic anisotropy in both types of films. This finding provides a better understanding of the magnetic domain landscape in GaMnAs that has been the subject of intense debate

Mechanism of peripheral nerve modulation and recent applications

Neuromodulation is a multi-interdisciplinary field of neuroscience, neural engineering, and medicine in a complex, but a way of understanding. Recently, the interest and researches in this field have been attracted due to its promising applications such as bionic limbs and bioelectronic medicine. For easier entry into this field, in this review, we approach the basic mechanism, methods, and applications of peripheral neuromodulation sequentially. Firstly, the overall structure and functions of the human nervous system are introduced, especially in the peripheral nervous system (PNS). Specifically, the fundamental neurophysiology regarding action potentials and neural signals is introduced to understand the communication between the neurons. Thereafter, two main methods for peripheral neuromodulation, which are electrical and optogenetic approaches, are introduced with the principles of the state-of-art devices. Finally, advanced applications of neuromodulation combined with the sensor, stimulator, and controller, called a closed-loop system are introduced with an example of bionic limbs. © 2021 The Author(s). Published with license by Taylor & Francis Group, LLC.1

Coyote C++: An Industrial-Strength Fully Automated Unit Testing Tool

Coyote C++ is an automated testing tool that uses a sophisticated concolic-execution-based approach to realize fully automated unit testing for C and C++. While concolic testing has proven effective for languages such as C and Java, tools have struggled to achieve a practical level of automation for C++ due to its many syntactical intricacies and overall complexity. Coyote C++ is the first automated testing tool to breach the barrier and bring automated unit testing for C++ to a practical level suitable for industrial adoption, consistently reaching around 90% code coverage. Notably, this testing process requires no user involvement and performs test harness generation, test case generation and test execution with "one-click" automation. In this paper, we introduce Coyote C++ by outlining its high-level structure and discussing the core design decisions that shaped the implementation of its concolic execution engine. Finally, we demonstrate that Coyote C++ is capable of achieving high coverage results within a reasonable timespan by presenting the results from experiments on both open-source and industrial software

Repurposing metformin for cancer treatment: current clinical studies.

In recent years, several studies have presented evidence suggesting a potential role for metformin in anti-cancer therapy. Preclinical studies have demonstrated several anticancer molecular mechanisms of metformin including mTOR inhibition, cytotoxic effects, and immunomodulation. Epidemiologic data have demonstrated decreased cancer incidence and mortality in patients taking metformin. Several clinical trials, focused on evaluation of metformin as an anti-cancer agent are presently underway. Data published from a small number of completed trials has put forth intriguing results. Clinical trials in pre-surgical endometrial cancer patients exhibited a significant decrease in Ki67 with metformin monotherapy. Another interesting observation was made in patients with breast cancer, wherein a trend towards improvement in cancer proliferation markers was noted in patients without insulin resistance. Data on survival outcomes with the use of metformin as an anti-cancer agent is awaited. This manuscript will critically review the role of metformin as a potential cancer treatment

On Translation Lengths of Anosov Maps on Curve Graph of Torus

We show that an Anosov map has a geodesic axis on the curve graph of a torus. The direct corollary of our result is the stable translation length of an Anosov map on the curve graph is always a positive integer. As the proof is constructive, we also provide an algorithm to calculate the exact translation length for any given Anosov map. The application of our result is threefold: (a) to determine which word realizes the minimal translation length on the curve graph within a specific class of words, (b) to establish the effective bound on the ratio of translation lengths of an Anosov map on the curve graph to that on Teichm\"uller space, and (c) to estimate the overall growth of the number of Anosov maps which have a sufficient number of Anosov maps with the same translation length.Comment: 32 pages, 14 figure