Oscillator Phase Noise and Small-Scale Channel Fading in Higher Frequency Bands

This paper investigates the effect of oscillator phase noise and channel variations due to fading on the performance of communication systems at frequency bands higher than 10GHz. Phase noise and channel models are reviewed and technology-dependent bounds on the phase noise quality of radio oscillators are presented. Our study shows that, in general, both channel variations and phase noise can have severe effects on the system performance at high frequencies. Importantly, their relative severity depends on the application scenario and system parameters such as center frequency and bandwidth. Channel variations are seen to be more severe than phase noise when the relative velocity between the transmitter and receiver is high. On the other hand, performance degradation due to phase noise can be more severe when the center frequency is increased and the bandwidth is kept a constant, or when oscillators based on low power CMOS technology are used, as opposed to high power GaN HEMT based oscillators.Comment: IEEE Global Telecommun. Conf. (GLOBECOM), Austin, TX, Dec. 201

Calculation of the Performance of Communication Systems from Measured Oscillator Phase Noise

Oscillator phase noise (PN) is one of the major problems that affect the performance of communication systems. In this paper, a direct connection between oscillator measurements, in terms of measured single-side band PN spectrum, and the optimal communication system performance, in terms of the resulting error vector magnitude (EVM) due to PN, is mathematically derived and analyzed. First, a statistical model of the PN, considering the effect of white and colored noise sources, is derived. Then, we utilize this model to derive the modified Bayesian Cramer-Rao bound on PN estimation, and use it to find an EVM bound for the system performance. Based on our analysis, it is found that the influence from different noise regions strongly depends on the communication bandwidth, i.e., the symbol rate. For high symbol rate communication systems, cumulative PN that appears near carrier is of relatively low importance compared to the white PN far from carrier. Our results also show that 1/f^3 noise is more predictable compared to 1/f^2 noise and in a fair comparison it affects the performance less.Comment: Accepted in IEEE Transactions on Circuits and Systems-I: Regular Paper

Kan juridik ta hänsyn till erotisk praktik? - En studie av möjligheten att i en rättslig bedömning beakta handlingsnormer för BDSM-utövning.

BDSM is a variety of erotic practices that has received increased attention in recent years, in a legal context mainly through a number of rape trials where the accused was found not-guilty. In the cases, the accused's conviction that the violence was applied in a sexual context within a voluntary role-play resulted in a verdict of not guilty, this despite the fact that the court found that there was no valid consent and that the victim had objectively been forced to intercourse. The judgments have resulted in an concern that an objection to BDSM has begun to be used only as a mean of justifying violence. It has been demanded that the courts should have more knowledge of the common principles of action standards in the BDSM community. The purpose of this paper has been to investigate and introduce these BDSM action standards in a legal context. The paper investigates how the judicial assessment can take generally accepted action standards in the BDSM community into account when an accused refers to such practice. This in light of the fact that the Swedish government has submitted a bill on the introduction of a new rape crime in which criminal liability is imposed on the person who is grossly negligence regarding the fact that the other person does not participate voluntarily. In order to fulfill the purpose of the paper, the relevant law and the government's proposals are investigated and two legal cases from the court of appeal are analyzed. The paper finds that the action standards within the BDSM culture convey similar approaches based on consent, caution, risk awareness, knowledge and communication. The paper argues that an objection to BDSM should be accepted only if it can be shown that such practice was agreed. Such awareness, along with a new criminal responsibility for negligence, may impose greater responsibility on the potential perpetrator to check for consent. This would provide better conditions to protect the sexual integrity for victims within non-normative sexual practices.BDSM är en grupp erotiska tekniker som blivit allt mer uppmärksammade de senaste åren, ur juridiskt perspektiv genom ett antal friande våldtäktsdomar. I målen har den tilltalades övertygelse om att våldet tillämpades i en sexuell kontext inom ramen för ett frivilligt rollspel resulterat i en friande utgång på grund av uppsåtsbrist. Detta trots att domstolen konstaterat att det inte förelegat giltigt samtycke och att målsäganden objektivt sett tvingats till samlag. Målen har resulterat i en oro att en invändning om BDSM har börjat användas som ett sätt att rättfärdiga våldsutövning. Det har efterfrågats en ökad kunskap hos domstolarna om de handlingsnormer som finns inom BDSM-kulturen. Syftet med denna uppsats har varit att undersöka och introducera dessa handlingsnormer i ett juridiskt sammanhang. Uppsatsen utreder på vilket sätt den rättsliga bedömningen kan ta hänsyn allmänt accepterade handlingsnormerna vid BDSM-utövning när en tilltalad hänvisar till en sådan. Detta i ljuset av att regeringen lämnat en proposition om införandet av ett nytt våldtäktsbrott där straffansvar införs för den som är grovt oaktsam beträffande omständigheten att den andra personen inte deltar frivilligt. För att uppfylla detta syfte utreds gällande rätt och regeringens förslag. Två rättsfall från underrätterna analyseras där den tilltalade har hävdat att samtycke funnits till sex med våldsinslag. I uppsatsen framkommer att ramverken inom BDSM-kulturen förmedlar snarlika förhållningssätt med utgångspunkt i samtycke, försiktighet, riskmedvetenhet, kunskap och kommunikation. Det förs en argumentation kring att en invändning om BDSM enbart bör godtas om det kan visas att det faktiskt varit fråga om en sådan utövning. En sådan medvetenhet tillsammans med ett oaktsamhetsbrott för våldtäkt kan innebära att ett större ansvar läggs på våldsutövaren att kontrollera att samtycke föreligger. Då skulle skyddet för den sexuella integriteten i större utsträckning kunna tillgodoses för utsatta inom normavvikande sexuella praktiker

A 24 GHz Sub-Harmonically Pumped Resistive Mixer in GaN HEMT Technology

—This paper presents the design and the characterization of a 24 GHz sub-harmonically pumped resistive mixer (SHM) in an advanced gallium nitride (GaN) high electron mobility transistor (HEMT) technology. The mixer is desired for building up a high-performance phaselocked W-band signal source, and is designed in a singlebalanced configuration, where the balanced LO input is generated by an on-chip first order lattice balun. In measurement, a conversion loss around 12 dB is achieved at the RF bandwidth of 22-28 GHz and the IF bandwidth of 3-6 GHz with a LO power of 10 dBm. The mixer exhibits an RF input P1dB of 13 dBm, and the measured LO to IF isolation achieves 40 dB at the desired LO of 10 GHz. To the best of the author’s knowledge, this is the first sub-harmonically pumped mixer in GaN HEMT technology

Modulation of invariant NKT cell activity by cytokines and receptors in human disease

Invariant natural killer T (NKT) cells are innate-like lymphocytes with both immunoregulatory and cytotoxic functions that play a role as activators and regulators of the immune response in many diseases. NKT cells are believed to bridge the innate and adaptive immune systems by rapidly producing large quantities of cytokines after recognition of CD1d-presented lipid antigens. NKT cells can be divided into two phenotypically and functionally distinct subsets based on the expression of CD4. How the NKT cells and their subsets are regulated, and how they integrate signals from their environment to modulate immune responses is still not fully understood. In this thesis I have investigated how the activity of NKT cells can be modulated by factors other than the TCR, such as cell surface receptors and cytokines. These investigations have been based on blood samples from healthy controls, and from patients suffering from HIV-1 infection or atopic eczema (AE). We have found that CD4- NKT cells are able to degranulate and kill target cells in an NKG2D-dependent but TCR-independent manner in response to NKG2D stimulus. Moreover, we have shown that NKG2D+ NKT cells frequently express perforin that polarizes toward NKG2D-ligand expressing tumor cells. These data demonstrate that the CD4- subset of human NKT cells can mediate direct lysis of CD1d-negative target cells upon NKG2D engagement. We have further characterized the phenotype and function of NKT cells in patients with chronic diseases. In patients with chronic HIV- 1 infection, the CD4- NKT cell subset showed increased expression of the inhibitory programmed death-1 (PD-1) receptor, and displayed severe functional defects. However, the functional impairment was not caused by PD-1 expression per se because the defect could not be reversed by PD-1 blockade. In addition, we have studied the effect of interleukin-2 (IL-2) on NKT cells and natural killer (NK) cells in patients with chronic HIV-1 infection. Material for this study was obtained from a longitudinally study, where administration of IL-2 was added to the antiretroviral treatment (ART) for one year. We found that NKT cells and NK cells responded with different kinetics and in different ways to the IL-2 administration. The NKT cells responded with a gradual numerical increase, but with no significant functional changes. NK cells responded rapidly with an expansion of the cytotoxic CD56dim NK cell subset and increased IFN-γ production. However, the effects of IL-2 on these cells were generally not sustained post treatment. NKT cells were also studied in the chronic inflammatory skin disease AE where the patients have elevated levels of plasma IL-18. Our data provide evidence that IL-18 is a potent activator of human NKT cells promoting an acute pro-inflammatory CD1d-dependent response, even in the absence of exogenous lipid antigens. Interestingly, chronic exposure of NKT cells to IL-18 is inhibitory and skews the NKT cell pool by selectively suppressing the proliferation of CD4+ NKT cells. Importantly, our in vitro data are reflected in AE patients where reduced numbers of CD4+ NKT cells are associated with elevated levels of IL-18 and disease severity. In conclusion, the work presented here contributes to our understanding of the function and role of NKT cells in human diseases including infections and allergie

25 GHz and 28 GHz Wide Tuning Range 130 nm CMOS VCOs with Ferroelectric Varactors

Two 130nm CMOS VCOs with ferroelectric varactors are presented. The cross-coupled VCO-cores are flip-chip mounted on silicon carriers with integrated inductors and tunable ferroelectric varactors. The output frequency of the first VCO is tunable from 23.4 GHz to 26.1 GHz, corresponding to a tuning range of 11 %. The phase noise of this VCO, tuned to its center frequency, measures -117 dBC/Hz at 1 MHz offset and the power consumption is 18 mW. The second VCO is tunable from 25.8 GHz to 30.5 GHz, corresponding to a tuning range of 17 %. The phase noise at center frequency for this design measures -109 dBc/Hz and the power consumption is 5.3 mW

Towards Machine Learning on data from Professional Cyclists

Professional sports are developing towards increasingly scientific training methods with increasing amounts of data being collected from laboratory tests, training sessions and competitions. In cycling, it is standard to equip bicycles with small computers recording data from sensors such as power-meters, in addition to heart-rate, speed, altitude etc. Recently, machine learning techniques have provided huge success in a wide variety of areas where large amounts of data (big data) is available. In this paper, we perform a pilot experiment on machine learning to model physical response in elite cyclists. As a first experiment, we show that it is possible to train a LSTM machine learning algorithm to predict the heart-rate response of a cyclist during a training session. This work is a promising first step towards developing more elaborate models based on big data and machine learning to capture performance aspects of athletes.Comment: Accepted for the 12th World Congress on Performance Analysis of Sports, Opatija, Croatia, 201

Mitigating the impacts of air pollutants in Nepal and climate co-benefits: a scenario-based approach

Short-lived climate pollutants (SLCPs) including black carbon (BC), methane (CH4), and tropospheric ozone (O3) are major climate forcers after carbon dioxide (CO2). These SLCPs also have detrimental impacts on human health and agriculture. Studies show that the Hindu Kush Himalayan (HKH) region, which includes Nepal, has been experiencing the impacts of these pollutants in addition to greenhouse gases. In this study, we derive a national-level emission inventory for SLCPs, CO2, and air pollutants for Nepal and project their impacts under reference (REF) and mitigation policy (POL) scenarios. The impacts on human health, agriculture, and climate were then estimated by applying the following: (1) adjoint coefficients from the Goddard Earth Observing System (GEOS)-chemical transport model that quantify the sensitivity of fine particulate matter (PM2.5) and surface O3 concentrations in Nepal, and radiative forcing in four latitudinal bands, to emissions in 2 × 2.5° grids, and (2) concentration–response functions to estimate health and crop loss impacts in Nepal. With the mitigating measures undertaken, emission reductions of about 78% each of BC and CH4 and 87% of PM2.5 could be achieved in 2050 compared with the REF scenario. This would lead to an estimated avoidance of 29,000 lives lost and 1.7 million tonnes of crop loss while bringing an economic benefit in present value of 2.7 times more than the total cost incurred in its implementation during the whole period 2010–2050. The results provide useful policy insights and pathways for evidence-based decision-making in the design and effective implementation of SLCP mitigation measures in Nepal

On Models, Bounds, and Estimation Algorithms for Time-Varying Phase Noise

In this paper, first, a new discrete-time model of phase noise for digital communication systems, which is a more accurate model compared to the classical Wiener model, is proposed based on a comprehensive continuous-time representation of time-varying phase noise, and statistical characteristics of this model are derived. Next, the non-data-aided (NDA) and decision-directed (DD) maximum-likelihood (ML) estimators of time-varying phase noise, using the proposed discrete-time model are derived. To evaluate the performance of the proposed estimators, the Cramer-Rao lower bound (CRLB) for each estimation approach is derived and by using Monte-Carlo simulations it is shown that the mean-square error (MSE) of the proposed estimators converges to the CRLB at moderate signal-to-noise ratios (SNR). Finally, simulation results show that the proposed estimators outperform existing estimation methods as the variance of the phase noise process increases