Differential Privacy of Aggregated DC Optimal Power Flow Data

We consider the problem of privately releasing aggregated network statistics obtained from solving a DC optimal power flow (OPF) problem. It is shown that the mechanism that determines the noise distribution parameters are linked to the topology of the power system and the monotonicity of the network. We derive a measure of "almost" monotonicity and show how it can be used in conjunction with a linear program in order to release aggregated OPF data using the differential privacy framework.Comment: Accepted by 2019 American Control Conference (ACC

System Level Synthesis

This article surveys the System Level Synthesis framework, which presents a novel perspective on constrained robust and optimal controller synthesis for linear systems. We show how SLS shifts the controller synthesis task from the design of a controller to the design of the entire closed loop system, and highlight the benefits of this approach in terms of scalability and transparency. We emphasize two particular applications of SLS, namely large-scale distributed optimal control and robust control. In the case of distributed control, we show how SLS allows for localized controllers to be computed, extending robust and optimal control methods to large-scale systems under practical and realistic assumptions. In the case of robust control, we show how SLS allows for novel design methodologies that, for the first time, quantify the degradation in performance of a robust controller due to model uncertainty -- such transparency is key in allowing robust control methods to interact, in a principled way, with modern techniques from machine learning and statistical inference. Throughout, we emphasize practical and efficient computational solutions, and demonstrate our methods on easy to understand case studies.Comment: To appear in Annual Reviews in Contro

One lumbar extension training session per week is sufficient for strength gains and reduction in pain in patients with chronic low back pain ergonomics

Chronic low back pain (CLBP) is the leading cause of absenteeism from the workplace and research into exercise interventions to address this problem is required. This study investigated training frequency for participants with CLBP. Participants either trained once a week (1 × week, n = 31), or twice a week (2 × week, n = 20) or did not (control group, n = 21). Participants were isometric strength tested in weeks 1 and 12 and trained dynamically either 1×week (80% of maximum) or 2×week (80% and 50%). The results (pre vs. post) showed significant increases in maximal strength, range of motion and reductions in pain for both training groups. Pain scores for the 1 × week and 2 × week both reached minimal clinical improvement change unlike the control group. Thus, one lumbar extension training session per week is sufficient for strength gains and reductions in pain in low back pain in CLBP patients

Can cash transfer programs work in resource-poor countries?

Cash transfer programs are rare in Sub-Saharan Africa. This paper describes the evolution of a cash transfer program in major urban centers of Mozambique, from its inception in 1990 through two major reorganizations until October 1998. Appropriate design, strong multisectoral political support and adequate administrative capacity are critical factors determining the success of such programs. Key lessons applicable to other resource-poor countries designing social assistance programs are drawn, recommending adequate targeted support to truly destitute persons incapable of physical labor in urban areas where administrative costs are more manageable than in more isolated rural sites.Poverty. ,Rural population. ,Social service Mozambique. ,Subsidies. ,

Adolescents as future housing consumers: a study of housing aspirations

The research looks first at the process of urban growth, in an attempt to establish a residential framework. By then relating urban growth and the housing market to the physical situation enables one to determine the choice in housing.The survey methodology establishes the use and nature of the questionnaire and the priority evaluation game which was developed to obtain the adolescents' housing priorities. The data collected from the survey of the adolescent sample is analysed enabling us to explore the attitudes of the future consumers. The research highlights the lack of information on housing preferences.The findings illustrate what is referred to as "conventional wisdom ". The desire is for owner- occupation and the detached or semi -detached house with a garden. And although the findings do not show a complete rejection of the city, they do indicate a widespread desire to move to suburban areas. This urge for suburban life is not limited to the middle class, it is representative of all social classes. If the results are indicative, the movement to suburban areas promises to continue through the next few decades. Once the move to suburbia has been made the pressure to stay there is very great.We cannot continue to encourage home -ownership and a surburban way of life that is reinforced by the cultural norms and propogated by the media then deny access to our adolescents. We are in danger through our economic situation, of long term unemployment amongst adolescents, of creating a dangerous situation that could erupt if prolonged - a social explosion

Compositional Set Invariance in Network Systems with Assume-Guarantee Contracts

This paper presents an assume-guarantee reasoning approach to the computation of robust invariant sets for network systems. Parameterized signal temporal logic (pSTL) is used to formally describe the behaviors of the subsystems, which we use as the template for the contract. We show that set invariance can be proved with a valid assume-guarantee contract by reasoning about individual subsystems. If a valid assume-guarantee contract with monotonic pSTL template is known, it can be further refined by value iteration. When such a contract is not known, an epigraph method is proposed to solve for a contract that is valid, ---an approach that has linear complexity for a sparse network. A microgrid example is used to demonstrate the proposed method. The simulation result shows that together with control barrier functions, the states of all the subsystems can be bounded inside the individual robust invariant sets.Comment: Submitted to 2019 American Control Conferenc

Looking for a light Higgs boson in the overlooked channel

The final state obtained when a Higgs boson decays to a photon and a Z boson has been mostly overlooked in current searches for a light Higgs boson. However, when the Z boson decays leptonically, all final state particles in this channel can be measured, allowing for accurate reconstructions of the Higgs mass and angular correlations. We determine the sensitivity of the Large Hadron Collider (LHC) running at center of masses energies of 8 and 14 TeV to Standard Model (SM) Higgs bosons with masses in the 120 - 130 GeV range. For the 8 TeV LHC, sensitivity to several times the the SM cross section times branching ratio may be obtained with 20 inverse femtobarns of integrated luminosity, while for the 14 TeV LHC, the SM rate is probed with about 100 inverse femtobarns of integrated luminosity.Comment: 4 pages, 4 figures. Improves on version 1 in that 8 and 14 TeV LHC running is considered, the case of a 125 GeV Higgs is treated specifically, and the effect of an additional jet in the final state has been taken into account in studying experimental sensitivit

Time-motion and heart-rate characteristics of adolescent female foil fencers

Purpose: The aims of this study was to understand the time-motion and heart-rate characteristics of adolescent female foil fencing, explore the differences between the 5-touch and 15-touch bouts and compare these results with previous analysis of elite female foil fencers. Methods: Eight adolescent female foil fencers (age 14.3 ± 1.2 y, stature 157 ± 3.8 cm, body mass 45.9 ± 5.2 kg) were analysed at a youth fencing competition. Each fencer wore a heart-rate monitor throughout the competition and bouts were filmed so time-motion analysis could be carried out. Five movement classifications were used for the time-motion analysis, this were grouped into three categories based on movement intensity: Low, Moderate and High. Results: High-intensity movement accounted for 8.8 ± 4.4 % of total bout time with a mean duration of 0.8 ± 0.2 s. A higher percentage of low-intensity movement was recorded in the 15-touch bouts, with a higher percentage of high-intensity movement recorded in the 5-touch bouts. The mean duration of low-intensity movement was longer in the 15-touch bouts compared to the 5-touch bouts and a higher mean heart-rate was recorded in the 15-touch bouts compared to the 5-touch bouts. Conclusions: The results from this study suggest that adolescent female foil fencers perform a greater percentage of high-intensity movement in 5-touch bouts compared to 15-touch bouts. However, these fencers demonstrate a higher heart-rate in the 15-touch bouts. The practical application of this study is that adolescent female foil fencers must have a strong aerobic base to maintain a lower heart-rate in competition and ensure that fatigue does not become a limiting factor to performance