Usage Period Research Articles

Demographic data and fi gures derived from Estonian Iron Age graves

Three Iron Age cremation graves from south-eastern Estonia and four graves including cremations as well inhumations from western Estonia were analysed by osteological and palaeodemographic methods in order to estimate the age and sex composition of burial sites, and to propose some possible demographic figures and models for living communities.
 The crude birth/death rate estimated on the basis of juvenility indices varied between 55.1‰ and 60.0‰ (58.5‰ on average) at Rõsna village in south-eastern Estonia in the Middle Iron Age. The birth/death rates based on juvenility indices for south eastern graves varied to a greater degree. The estimated crude birth/death rate was somewhat lower (38.9‰) at Maidla in the Late Iron Age and extremely high (92.1‰) at Maidla in the Middle Iron Age, which indicates an unsustainable community. High crude birth/death rates are also characteristic of Poanse tarand graves from the Pre-Roman Iron Age – 92.3‰ for the 1st grave and 69.6‰for the 2nd grave. Expectedly, newborn life expectancies are extremely low in both communities – 10.8 years at Poanse I and 14.4 years at Poanse II. Most likely, both Maidla I and Poanse I were unsustainable communities.
 According to the main model where the given period of grave usage is 150 years, the burial grounds were most likely exploited by communities of 3–14 people. In most cases, this corresponds to one family or household. In comparison with other graves, Maidla II stone grave in western Estonia and Rõsna-Saare I barrow cemetery in south-eastern Estonia could have been used by a somewhat larger community, which may mean an extended family, a larger household or usage by two nuclear families.

Long-Term (1970-2017) Temporal Trends of Polychlorinated Biphenyls in Fish, Settling Material, and Sediments from Populated and Remote Sites in Río de la Plata Estuary, Argentina.

Temporal trends of polychlorinated biphenyls (PCBs) were studied for detritivorous fish (1996-2017) and settling material (2002-2017) from polluted Buenos Aires coast and for a dated sediment core (1970-2013) from the outer Río de la Plata estuary. In spite of contrasting concentrations [5.3 ± 6.3 μg·g-1 dry weight (dw) for fish, 48 ± 26 ng·g-1 dw for settling material, and 1.5 ± 0.7 ng·g-1 dw for core], all three revealed exponentially decreasing trends over time (97%, 83%, and 83%, respectively). Time trends showed peak maxima coincident with Argentina's period of maximum PCB usage in 1973-1980 (80 cm depth in the core) and pulse discharges related to PCB banning in 2001-2002 (fish) with a lighter signature enriched in less persistent tri- and tetrachlorobiphenyls. The log-linear PCB time trends compare well with the predicted decrease for a high emission scenario from global emission data; the best fit was observed for the less impacted sediment core (-2%·year-1 versus -3%·year-1 for emission scenario). Steeper slopes are observed for the more polluted settling material (-5%·year-1) and especially for fish, in which the background decline trend tripled after the 2001 PCB pulse (from -7%·year-1 to -21%·year-1). These PCB time trends in related environmental compartments from contrasted sites provide rare evidence for evaluating the effectiveness of control measures in southern South America.

Vacuum bell treatment of pectus excavatum: An early North American experience

PurposeConservative treatment of pectus excavatum with a vacuum bell device may be an attractive alternative to surgical repair. We describe an early North American experience with this device. MethodsProspectively maintained chest wall clinic registries from two institutions were reviewed to identify pectus excavatum patients ≤21 years treated with the vacuum bell from 2013 to 2017. Multivariate linear regression was used to compare mean improvements in deformity-depth and Haller Index between groups of patients based on age and usage metrics (hours/day and days/week). ResultsThirty-one patients with a median age of 14 years received treatment with the device. Mean follow-up duration was 18 months. Median depth and Haller Index at treatment onset were 2.3 cm and 3.9, respectively. Improvements in deformity-depth were superior with device usage >2 h/day (p < 0.01) and daily use (p < 0.01). After adjusting for compliance, younger age of treatment onset was associated with greater improvement in Haller Index but not deformity depth. ConclusionOur prospective early North American experience found the vacuum bell to be a potential alternative to surgical treatment for pectus excavatum. Longer usage periods in a daily frequency are associated with best results. Type of studyTreatment study; case series with no comparison group. Level of evidenceLevel IV.

TYPE 2 DIABETES AND CARDIOVASCULAR COMPLICATIONS: IS IT POSSIBLE TO IMPROVE PROGNOSIS BY GLUCOSE LOWERING THERAPY?

Regardless the fact that type 2 diabetes (DM2) is related to higher risk of cardiovascular diseases (CVD) development and complications, incl. heart failure (HF), usage of the most of glucose lowering drugs (GLD) does not only improve life prognosis, but might increase the risk of HF. Inhibitors of SGLT2 (gliflozines), a novel group of GLD with a unique non-insulin dependent mechanism of action, in a range of large randomized trials passed not only the obligatory test on cardiovascular safety, but have demonstrated ability to decrease the risk of combination endpoint development (cardiovascular mortality, non-fatal MI and strokes) and possibility for HF hospitalization. The conclusions of randomized trials are confirmed by real clinical practice of DM2 patients management, analyzed in large multicenter trials CVD-REAL, CVD-REAL-2. Inthese trials, first time prescribed SGLT2 inhibitors (in Europe, in most cases dapagliflozin) showed significant benefits for other classes of firstly prescribed GLD in a matter of hospitalization risks for HF or all-cause mortality. However, the total period of the gliflozines usage is not that long, so an answer to the question on stability of their effects in broader perspective is expected by the end of ongoing trials in patients with high cardiovascular risk and in HF patients, including those with no DM2.

Counterproductive effects of gamification: An analysis on the example of the gamified task manager Habitica

Abstract The concept of gamification has evoked increasing attention in HCI research and practice. Gamification uses game elements in serious, non-game contexts in order to motivate a particular target behavior or attitude change (e.g., sustainable behavior, physical activity, task management). While gamification has been attributed a high potential, a critical question is whether it actually induces the intended effect. The present research explores ``counterproductive effects of gamification'', i.e., cases when a gamification element does not encourage the intended behavior but rather the opposite (e.g., procrastination instead of getting things done). Studying the example of the gamified task manager Habitica, our paper reports insights from two consecutive studies. Study 1, a qualitative interview study based on interpretative phenomenological analysis (IPA) with one single user revealed seven themes describing distinct counterproductive effects in Habitica, and additional seven themes related to Habitica's reward/punishment system and psychological reactions to counterproductive effects. Study 2 further explored these findings in a quantitative field study with 45 users over a two-week usage period, also studying correlations to user experience, product evaluation, motivation to play Habitica and individual belief in gamification. All participants experienced counterproductive effects to some degree, whereby some effects (e.g., being punished by Habitica in especially productive times, since one does not manage to check off tasks in time) were more prevalent than others (e.g., relabeling tasks as positive habits with no due date to prevent the risk of punishments). The prevalence of counterproductive effects was correlated to the users' perceived inappropriateness of the reward system, and a crucial predictor for motivation change over time. Relations to psychological mechanisms, general implications for gamification design and future research directions are discussed.

Scheduling and economic analysis of hybrid solar water heating system based on timer and optimal control

In this paper, an optimal control approach is modelled and applied to a hybrid solar electric water heater. The hot water consumption profile of a medium density household is considered. Real historic exogenous data obtained from a weather station in the region is used as input for the developed model. The aim is to assess the cost saving potential the system can achieve under time-based pricing structure enforced by the electricity supplier in the region, while maintaining the desired temperature level of the hot water user. As a baseline, the operation of a timer-based thermostatically controlled scheme, the most commonly used method of control to minimize the energy usage and in turn the costs, is simulated. Comparisons between the operation of the HSWH with timer-based control and the optimally controlled HSWH presented a cost saving of 84.39% in the winter and 15.50% during summer period. Annual cost savings of 32.86% were noted. Additionally, the energy usage periods of the system are shifted to low demand regions of residential load profiles, decreasing the strain on the national electricity grid.

From the Chief Executive and News

From the Chief Executive and News

Mean Field Games in Nudge Systems for Societal Networks

We consider the general problem of resource sharing in societal networks, consisting of interconnected communication, transportation, energy, and other networks important to the functioning of society. Participants in such network need to take decisions daily, both on the quantity of resources to use as well as the periods of usage. With this in mind, we discuss the problem of incentivizing users to behave in such a way that society as a whole benefits. To perceive societal level impact, such incentives may take the form of rewarding users with lottery tickets based on good behavior and periodically conducting a lottery to translate these tickets into real rewards. We will pose the user decision problem as a mean field game and the incentives question as one of trying to select a good mean field equilibrium (MFE). In such a framework, each agent (a participant in the societal network) takes a decision based on an assumed distribution of actions of his/her competitors and the incentives provided by the social planner. The system is said to be at MFE if the agent’s action is a sample drawn from the assumed distribution. We will show the existence of such an MFE under general settings, and also illustrate how to choose an attractive equilibrium using as an example demand-response in the (smart) electricity network.

The functional, spatio-temporal and satisfaction outcomes of transtibial amputees with a hydrocast socket following an extended usage period in an under-resourced environment

BackgroundTranstibial hydrocast sockets have been shown to be a potential alternative to hand-cast patella-tendon bearing sockets, the use of which would have particular benefits in under-resourced environments. However, data concerning wearer outcomes of hard hydrocast sockets (i.e. those without silicone liners), especially over long-term usage periods, is scarce in the literature. Research questionsAre there any changes in wearer functional, spatio-temporal or satisfaction outcomes over a long usage period with a hydrocast socket? And how do the post-usage period outcomes compare with those from the wearers original prostheses? MethodsIn this pre-post interventional study, the clinical outcomes of twenty-one experienced transtibial prostheses users were evaluated using widely-accepted and employed methods to assess wearer functional capacity, mobility, gait and satisfaction. The participants were fit with a hard hydrocast socket and the outcomes after an extensive usage period of 5 months were compared to the pre-usage period data following initial fitting and the data collected from the participants’ original prosthetic limb. ResultsSignificant differences were found in the temporal parameters of gait, all indicating decreased reliance on the intact limb and an increased loading of the prosthetic limb with the post-usage period hydrocast socket compared to both the pre-usage period socket and the participants’ original limbs. No differences in the functional capacity, mobility, spatial gait parameters or satisfaction were found between the socket conditions. SignificanceThis is the largest study to date of functional, spatio-temporal and satisfaction outcomes of hydrocast sockets following an extended usage period in an under-resourced environment.

Autonomous Flexible Sensors for Health Monitoring.

A concise, although admittedly non-exhaustive, didactic summary is given of some of the main concepts and approaches related to recent advances and developments to enable autonomous detection and monitoring of the likelihood or existence of a health risk state in continuous and real-time modes. To give a comprehensive statement, different aspects of these advanced materials and related devices are presented and discussed, such as: flexible sensors used for non-invasive detection of health-related physiological markers; self-powered materials to enable extended usage periods by harvesting energy from body movement and temperature; and self-healing properties of the materials used on the wearable devices to enable extended usage periods if scratched or cut. The linkage of these advanced materials and technologies together is particularly specified. Some of the strong and weak points in the development of each wearable material/device are clearly highlighted and criticized. Several ideas regarding further improvement of skin-based wearable devices are also discussed.

Effect of processing parameters and controlled environment storage on the disproportionation and dissolution of extended-release capsule of phenytoin sodium

Phenytoin sodium (PS) is a narrow therapeutic index drug that dictates maintenance of narrow plasma concentration of the drug. This requires a good quality product that meets regulatory specifications throughout shelf-life as well as during the usage period. Quality of the drug product may change if not develop in a scientific fashion which may have ramifications on clinical outcome. The focus of the study was to understand the effect of process variables and storage conditions on the disproportionation and phase transformation of the drug, and dissolution of extended-release capsules of PS. Four formulations were prepared to contain either powder blend or granules of PS with commonly used excipients. The granules were prepared in a high shear mixture by granulating with water, ethanol or mixture thereof. The capsules were stored in pharmacy vials for 4-weeks at 40 °C/75% RH and 30 °C/65% RH. Formulations were characterized by spectroscopies (FTIR, NIR, and chemical imaging), X-ray powder diffraction (XRPD), dissolution and assay. Granules filled capsule did not meet USP dissolution specifications and there was a significant decrease in dissolution on exposure to stability conditions. Dissolution decreased from 77.56 ± 3.83% to 42.34 ± 4.31%, and 63.96 ± 6.12 to 46.53 ± 2.91 in physical mixture and water granulated formulations, respectively, after four weeks exposure at 40 °C/75% RH. Spectroscopic (NIR, FTIR, and chemical imaging) data indicated disproportionation of the drug during the storage period. Moreover, XRPD data explained a decrease in dissolution in the initial granules filled capsules as well as temperature and humidity exposed samples. It indicated the phase transformation of the drug and/or excipients, disproportionation and/or interactions. These changes further accelerated on exposure to stability conditions. In conclusion, our studies indicated the significant effect of process variables and stability conditions on the critical quality attributes of PS extended-release capsule that has the potential impact on the clinical performance of the product.

Occurrence of halogenated organic contaminants in estuarine sediments from a biosphere reserve in Southern Atlantic

The occurrence, distribution, and the total mass of polychlorinated biphenyls (PCBs) and organochlorine pesticides (OCPs) were studied in surficial sediments of the Paranaguá Estuarine System (PES), a subtropical estuary in Southern Atlantic. Altogether, concentrations and inventories of contaminants ranged from <0.06 to 4.78 ng g−1 and < 0.13 to 10.47 ng cm−2, respectively. OCPs presented the higher total mass (10.85 kg) and a decreasing trend from the inner estuary towards the adjoining shallow shelf. The occurrence of PCBs was restricted to sites nearby urban and industrial areas, which accumulated ~80% of the total mass of PCBs. Although the level of contamination is low, the results refer to recent years, which mean that the actual values could be greater if sediments from periods of higher usage were analyzed. This study provides the first estimates of POPs (persistent organic pollutants) total mass in the PES, contributing to data for the Southern American inventories.

Why Some Like It Loud

The common practice of power infrastructure oversubscription in data centers exposes dangerous vulnerabilities to well-timed power attacks (i.e., maliciously timed power loads), possibly creating outages and resulting in multimillion-dollar losses. In this paper, we focus on the emerging threat of power attacks in a multi-tenant data center, where a malicious tenant (i.e., attacker) aims at compromising the data center availability by launching power attacks and overloading the power capacity. We discover a novel acoustic side channel resulting from servers' cooling fan noise, which can help the attacker time power attacks at the moments when benign tenants' power usage is high. Concretely, we exploit the acoustic side channel by: (1) employing a high-pass filter to filter out the air conditioner's noise; (2) applying non-negative matrix factorization with sparsity constraint to demix the received aggregate noise and detect periods of high power usage by benign tenants; and (3) designing a state machine to guide power attacks. We run experiments in a practical data center environment as well as simulation studies, and demonstrate that the acoustic side channel can assist the attacker with detecting more than 50% of all attack opportunities, representing state-of-the-art timing accuracy.

Increased Usage of Antiseptics Is Associated with Reduced Susceptibility in Clinical Isolates of Staphylococcus aureus.

ABSTRACTHospital-acquired infection is a major cause of morbidity and mortality, and regimes to prevent infection are crucial in infection control. These include the decolonization of vulnerable patients with methicillin-resistant Staphylococcus aureus (MRSA) carriage using antiseptics, including chlorhexidine and octenidine. Concern has been raised, however, regarding the possible development of biocide resistance. In this study, we assembled a panel of S. aureus isolates, including isolates collected before the development of chlorhexidine and octenidine and isolates, from a major hospital trust in the United Kingdom during a period when the decolonization regimes were altered. We observed significant increases in the MIC and minimum bactericidal concentration (MBC) of chlorhexidine in isolates from periods of high usage of chlorhexidine. Isolates with increased MICs and MBCs of octenidine rapidly emerged after octenidine was introduced in the trust. There was no apparent cross-resistance between the two biocidal agents. A combination of variable-number tandem repeat (VNTR) analysis, PCR for qac genes, and whole-genome sequencing was used to type isolates and examine possible mechanisms of resistance. There was no expansion of a single strain associated with decreased biocide tolerance, and biocide susceptibility did not correlate with carriage of qac efflux pump genes. Mutations within the NorA or NorB efflux pumps, previously associated with chlorhexidine export, were identified, however, suggesting that this may be an important mechanism of biocide tolerance. We present evidence that isolates are evolving in the face of biocide challenge in patients and that changes in decolonization regimes are reflected in changes in susceptibility of isolates.

User Generated SQL Queries Inform Evaluation of NSSP ESSENCE

Objective: The objective of this work is to describe the use and performance of the NSSP ESSENCE system by analyzing the structured query language (SQL) logs generated by users of the National Syndromic Surveillance Program’s (NSSP) Electronic Surveillance System for the Early Notification of Community-based Epidemics (ESSENCE).Introduction: As system users develop queries within ESSENCE, they step through the user-interface to select data sources and parameters needed for their query. Then they select from the available output options (e.g., time series, table builder, data details). These activities execute a SQL query on the database, the majority of which are saved in a log so that system developers can troubleshoot problems. Secondarily, these data can be used as a form of web analytics to describe user query choices, query volume, query execution time, and develop an understanding of ESSENCE query patterns.Methods: ESSENCE SQL query logs were extracted from April 1, 2016 to August 23th, 2017. Overall query volume was assessed by summarizing volume of queries over time (e.g., by hour, day, and week), and by Site. To better understand system performance the mean, median, and maximum query execution times were summarized over time and by Site. SQL query text was parsed so that we could isolate, 1) Syndromes queried, 2) Sub-syndromes queried, 3) Keyword categories queried, and 4) Free text query terms used. Syndromes, sub-syndromes, and keyword categories were tabulated in total and by Site. Frequencies of free text query terms were analyzed using n-grams, wordclouds, and term co-occurrence relationships. Term co-occurrence network graphs were used to visualize the structure and relationships among terms.Results: There were a total of 354,101 SQL queries generated by users of ESSENCE between April 1, 2016 and August 23rd, 2017. Over this entire time period there was a weekly mean of 4,785 SQL queries performed by users. When looking at 2017 data through August 23rd this figure increases to a mean of 7,618 SQL queries per week for 2017, and since May 2017 the mean number of SQL queries has increased to 10,485 per week. The maximum number of user generated SQL queries in a week was 29,173. The mean, median, and maximum query execution times for all data was 0.61 minutes, 0 minutes, and 365 minutes, respectively. When looking at only queries with a free text component the mean query execution time increases slightly to 0.94 minutes, though the median is still 0 minutes. The peak usage period based on number of SQL queries performed is between 12:00pm and 3:00pm EST.Conclusions: The use of NSSP ESSENCE has grown since implementation. This is the first time the ESSENCE system has been used at a National level with this volume of data, and number of users. Our focus to date has been on successfully on-boarding new Sites so that they can benefit from use of the available tools, providing trainings to new users, and optimizing ESSENCE performance. Routine analysis of the ESSENCE SQL logs can assist us in understanding how the system is being used, how well it is performing, and in evaluating our system optimization efforts.

Analysis of consumer behavior and energy calculation for phase end of life on stamped batik products

A product will enter the end of life phase when the usage period expires. End of life recycleis divided into three categories, namely reuse, recycle, and landfills. Reuse is transferring usage rights to others to be used for the same purpose. Recycle is utilising used goods as raw materials for other products. Landfills are putting used clothing to a garbage dump site. Consumers have different tendencies to the expired product. Stamped batik as a typical product of Solo also experiences the same treatment at the end of its life. This study has the objective of reviewing the consumer behaviour toward the stamp batik and calculating the energy needed in the final product period. Simapro 3.8.0.0 sofwate was used for the analysis. Based on consumer behaviour toward the end of product life, the stamped batik user mostly transfer the function of stamped batik to cleaning cloth or recycle (48.97%). The energy needed for the recycling process of stamped batik is 3.2 kPt. The energy resources of the landfill of stamped batik are 0,085 kPt. The electrical energy used for landfills of stamped batik is 14.4 MJ per year.

Effects Of A Smartphone-based Intervention On Adults’ Physical Activity, Self-efficacy, And Enjoyment

PURPOSE: Smartphone applications provide an opportunity for implementing physical activity (PA) interventions remotely. However, little research has been published to date on their effects. The purpose of the study was to test the effectiveness of efitbuddy, a theory-based PA smartphone application, on young adults’ PA and motivational beliefs through a four-week intervention. METHODS: A quasi-experimental design with control group was used to examine the effects of efitbuddy on participants’ PA. 274 college students (167 females, mean age = 19.35±2.09 years) attended baseline and posttests and change scores were computed for each dependent variable (DV). After the baseline test, participants in the intervention group (n=187) downloaded Efitbuddy and used it daily for four weeks. Efitbuddy was a smartphone application developed to promote individual’s PA and included four behavior change techniques such as self-monitoring, setting goals, and provision of general health information. PA participation, self-efficacy, and exercise enjoyment were selected as the DVs of the study. A Pearson’s correlation analysis was employed on the raw data to examine if the data were suitable for multivariate analyses. The results displayed moderate linear relationships between the pretest and posttest scores on three DVs. Therefore a 2 (group) x 2 (time) x 2 (gender) Multivariate Analysis of Variance (MANOVA) was conducted to examine the differences in the dependent variables. Wilk’s lambda was used to decide the statistical significance of the multivariate model. RESULTS: There were no multivariate statistically significant interactions for Group x Time x Gender (Wilks’s ? = 0.996, F(6, 269) = 0.687, P = 0.560), for Time x Gender (Wilks’s ? = 0.003, F(6, 269) = 0.508, P = 0.677), and for Group x Time (Wilks’s ? = 1, F(6, 269) = 0.008, P = 0.999). However, the results from the MANOVA yielded a significant interaction for Gender x Group (Wilks’s ? = 0.985 F(6, 269) = 2.720, P = 0.044). CONCLUSIONS: The results of the study demonstrate that efitbuddy has limited influence on young adults’ PA through a four-week period of time usage. These results echo previous studies exploring the relationship between smartphone applications and PA behaviors and more research is warranted for longer intervention with more vigorous engagement of usage.

Using of Proper Pavement Material for the Intersections with Slow-moving Traffic

Use of proper pavement material for some of intersections need special attention by road designers. At Camp Bondsteel-Kosovo on 2002 were built four road intersections using the concrete as pavement material. Heavy and slow-moving trucks that are turning or accelerating exposed these intersections to some of the highest stress level. After some years this intresections start deteriorating on their surface due to friction. The concrete pavements did not survive this period of usage and after eight years were removed and replaced with asphalt pavements. After more than seven years, the asphalt has shown minor distress but is still in good condition after years of outstanding service. This issue was resolved using aggregate and aggregate blend who meet higher standards. This blend of aggregate has high internal friction developing the degree of interlock needed to resist friction and or shearing. In this case, tough, durable aggregates were necessary, while rounded aggregate avoided in both the coarse and fine fractions. Due to slow-moving traffic on the hot weather, the binder has been selected with higher temperature grade than climate conditions. The asphalt section is still going strong after seven years.

Reproduction method for dried biomodels composed of poly (vinyl alcohol) hydrogels

Models mimicking the realistic geometries and mechanical properties of human tissue are requiring ever-better materials. Biomodels made of poly (vinyl alcohol) are particularly in demand, as they can be used to realistically reproduce the characteristics of blood vessels. The reproducibility of biomodels can be altered due to dehydration that is observed after long periods of usage. In order to improve their usability, one should consider the method used to reproduce them; however, few studies have reported a method reproduce biomodels. This study proposes a novel reproduction method for biomodels that allows them to quickly and easily reproduce their geometric and mechanical properties. Specimens of the dried biomodels were reformed through immersion in temperature-controlled water. Our results show that water at 35 °C can be effective to reproduce both the geometric and mechanical properties of the specimens. X-ray diffraction (XRD) measurements revealed that water immersion can reform the crystal structure of the pre-dried specimens, and images obtained using micro-computed tomography acquisition show that the geometry of the specimens can be reformed by water immersion without introducing any defects. These results indicate that the proposed method can lead to high reproducibility of both the original geometric and mechanical properties of the dried biomodels.

Why Some Like It Loud

The common practice of power infrastructure oversubscription in data centers exposes dangerous vulnerabilities to well-timed power attacks (i.e., maliciously timed power loads to overload the infrastructure capacity), possibly creating outages and resulting in multimillion-dollar losses. In this paper, we focus on the emerging threat of power attacks in a multi-tenant data center, where a malicious tenant (i.e., attacker) aims at compromising the data center availability through power attacks. We discover a novel acoustic side channel resulting from servers' cooling fan noise, which can help the attacker time power attacks at the moments when benign tenants' power usage is high. Concretely, we exploit the acoustic side channel by: (1) employing a high-pass filter to filter out the air conditioner's noise; (2) applying non-negative matrix factorization with sparsity constraint to demix the received aggregate noise and detect periods of high power usage by benign tenants; and (3) designing a state machine to guide power attacks. We run experiments in a practical data center environment as well as simulation studies, and demonstrate that the acoustic side channel can assist the attacker with detecting more than 50% of all attack opportunities, representing state-of-the-art timing accuracy.