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Designing multiple antennas in small terminals at frequency bands below 1 GHz is challenging due to severe mutual coupling among antenna elements. The severe coupling is often the result of simultaneous excitation of the fundamental characteristic mode of the terminal chassis by more than one antenna element. In this work, through the use of characteristic mode analysis, we propose to solve the co
Correlation coefficient, as a critical performance metric of multiple antenna systems, can be calculated from the 3D radiation patterns of the antennas for multipath environments with uniform 3D angular power spectrum. A simpler, faster and lower cost approach uses the antennas’ scattering parameters to determine correlation coefficient. However, the method assumes lossless antennas, and hence onl
Evaluation of Specific Absorption Rate (SAR) for multiple antenna systems is expected with the upcoming deployment of LTE Advanced, where multi-antennas are excited in both uplink and downlink. In this work, the influence of different antenna locations and antenna types was investigated for stand-alone SAR and simultaneous SAR, to provide some guidelines for antenna design in multi-antenna handset
Healthcare is increasingly a collaborative effort in- volving caregivers from several different organizations providing services to the same patient. This is particularly the case in care for the elderly and chronically ill, where a preference for care in the home is common. Current systems lack support for care scenarios that require mobility and intra-organizational collaboration. This results i
Technology scaling in advanced CMOS nodes has been very successful in reducing the cost and increasing the operating frequency, however, it has also resulted in reduced transistor intrinsic gain and increased thermal noise coefficient, and most importantly, deteriorated linearity performance. At the same time, advanced wireless communication standards offer ever increasing data rates and pose m
In this work, we analyze the use of a WiFi network deployed in a large-scale technical university. To this extent, we leverage three weeks of WiFi traffic data logs and characterize the spatio-temporal correlation of the traffic at different granularities (each individual access point, groups of access points, entire network). The spatial correlation of traffic across nearby access points is also
This paper presents a 2-dimension (2-D) Vernier time-to-digital converter (TDC) which uses two 3-stage gated-ring-oscillators (GROs) in the X/Y Vernier branches. The already small Vernier quantization noise (~10.6ps) is improved by the 1st-order noise shaping of the GRO. Moreover, since all delay differences between X phases and Y phases can be used (rather than only the diagonal line of the 1-dim
Numerous tools automating various aspects of software engineering have been developed, and many of the tools are highly configurable through parameters. Understanding the parameters of advanced tools often requires deep understanding of complex algorithms. Unfortunately, suboptimal parameter settings limit the performance of tools and hinder industrial adaptation, but still few studies address the
Implementation of open source development practices within commercial settings can bring benefits such as improved source code quality, lower maintenance costs, and increased innovation. However, a widespread in-house implementation of the practices has not been observed. The goal of this research is to understand factors which hinder the implementation. For the purpose, development practices of a
Objective. To determine the concentrations of aggrecan fragments in synovial fluid from patients with knee joint injury, osteoarthritis (OA), or acute pyrophosphate arthritis (PPA; pseudogout), and to test their relative reactivity with the 846 epitope, a putative marker of cartilage aggrecan synthesis. Methods. Samples of knee joint fluid from 385 patients and 9 healthy-knee volunteers were obtai
Software engineering considers performance evaluation to be one of the key portions of software quality assurance. Unfortunately, there seems to be a lack of standard methodologies for performance evaluation even in the scope of experimental computer science. Inspired by the concept of “instantiation” in object-oriented programming, we distinguish the generic performance evaluation logic from the
Today we have different location based services available in a mobile phone or mobile station (MS). These services include: direction finding to nearby ATMs, locating favorite food restaurants, or finding any target destination. Similarly, we see different applications of the positioning and navigation systems in firefighting or other rescue operations. The common factor in almost all of the locat
A 2.8-to-5.8 GHz harmonic VCO designed in a 28 nm UTBB FD-SOI CMOS process adopts a reconfigurable active core to save power at the lower oscillation frequencies, and to enable a trade-off between power consumption and phase noise at all frequencies. Interference caused by the magnetic coupling to and from the VCO inductor is greatly attenuated by resorting to an inductor in the shape of an 8. Sim
A 2.8-to-5.8GHz VCO designed in a 28nm UTBB FD-SOI CMOS process adopts a reconfigurable active core to save power at the lower oscillation frequencies, and to enable a trade-off between power consumption and phase noise at all frequencies. The UTBB FD-SOI CMOS process is instrumental to achieve a tuning range in excess of one octave at low power consumption, while the use of an 8-shaped tank coil
A digital phase-locked loop (DPLL) which uses a high resolution 2-dimension gated-Vernier time-to-digital converter (TDC) is presented. The shaped Vernier quantization of TDC greatly improves the in-band phase noise. Also the 2-dimension structure makes DPLL be able to process large phase errors almost without the influence of latency time. Combined with a high figure-of-merit (FOM) class-D digita
Empirical software engineering is a growing research area. Industrial experience gathered by systematic empirical case studies is extremely important for further evolution of the software engineering discipline. Scientific theory cannot provide effective means for software industry without fundamental understanding of the evolutionary development of complex software systems. However, there are cer
