TimeTrader: Exploiting Latency Tail to Save Datacenter Energy for On-line Data-Intensive Applications

Datacenters running on-line, data-intensive applications (OLDIs) consume significant amounts of energy. However, reducing their energy is challenging due to their tight response time requirements. A key aspect of OLDIs is that each user query goes to all or many of the nodes in the cluster, so that the overall time budget is dictated by the tail of the replies' latency distribution; replies see latency variations both in the network and compute. Previous work proposes to achieve load-proportional energy by slowing down the computation at lower datacenter loads based directly on response times (i.e., at lower loads, the proposal exploits the average slack in the time budget provisioned for the peak load). In contrast, we propose TimeTrader to reduce energy by exploiting the latency slack in the sub- critical replies which arrive before the deadline (e.g., 80% of replies are 3-4x faster than the tail). This slack is present at all loads and subsumes the previous work's load-related slack. While the previous work shifts the leaves' response time distribution to consume the slack at lower loads, TimeTrader reshapes the distribution at all loads by slowing down individual sub-critical nodes without increasing missed deadlines. TimeTrader exploits slack in both the network and compute budgets. Further, TimeTrader leverages Earliest Deadline First scheduling to largely decouple critical requests from the queuing delays of sub- critical requests which can then be slowed down without hurting critical requests. A combination of real-system measurements and at-scale simulations shows that without adding to missed deadlines, TimeTrader saves 15-19% and 41-49% energy at 90% and 30% loading, respectively, in a datacenter with 512 nodes, whereas previous work saves 0% and 31-37%.Comment: 13 page

Com parative investigation of adolescent’s communicational problems wtthparents from the points of view of these two groups.

داشتن رابطه خوب با والدین، برای همه بخصوص نوجوانان بسیار حائز اهمیت است. بسیاری از مشکلاتی که در دوره نوجوانی برای خانواده و نوجوان پیش می آید، ناشی از عدم وجود ارتباط باز بین والدین و نوجوان است. هدف از انجام این مطالعه بررسی و مقایسه مشکلات ارتباطی نوجوانان با والدین از دیدگاه آنان بوده است. این پژوهش، مطالعه ای توصیفی ـ تحلیلی و از نظر زمانی مقطعی است، که در دبیرستان های دولتی شهر اصفهان انجام گرفته است. در این پژوهش تعداد 415 نفر از نوجــوانان دختر و پسر و 230 مورد از والدین آنها به روش تصادفی ـ خوشه ای انتخاب شدند و مشکلات ارتباطی نوجوانان با والدینشان از دیدگاه نوجوانان و والدین مورد بررسی قرار گرفت. ابزار گردآوری داده ها پرسشنامه بود. بررسی و تجزیه و تحلیل های آماری نشان داد که بین دیدگاه های نوجوانان و والدین در رابطه با مشکلات ارتباطی نوجوانان و والدین در زمینه های استقلال طلبی، بلوغ جنسی و کسب شخصیت نوجوانان اختلاف معنی داری وجود داشت. نتایج پژوهش حاکی از تأثیر ارتباط سالم نوجوانان با والدین در زمینه های استقلال طلبی، بلوغ جنسی و کسب شخصیت، تضمین بهداشت روانی و کسب هویت نوجوان بود. سالمترین راه برای رسیدن به موارد فوق این است که روابط نوجوانان با والدین دائمی و صمیمی باشد. لذا به مسئولین بهداشت روانی و سیاسی اجتماعی جامعه پیشنهاد می گردد که به ارتباط در خانواده ها بخصوص در خانواده هایی که دارای فرزند نوجوان هستند،‌به عنوان یک تکنیک فراگیر و مهم در جهت پیشگیری اولیه بنگرند و نحوه ارتباط خانوادگی سالم را آموزش دهند

Effect of variety and spacing on the yield performance of maize (Zea mays L.) in old Brahmaputra floodplain area of Bangladesh

The experiments were conducted at the Agronomy Field Laboratory, Agricultural University, Mymensingh in Bangladesh during December 2015 to April 2016 to investigate the effect of variety and plant spacing on yield attributes and yield of maize. The experiment comprised of five varieties viz., Khoi bhutta, BARI hybrid maize 7, BARI hybrid maize 9, C-1921, P-3396 and five plants spacing viz., 75 cm × 20 cm, 75 cm × 25 cm, 75 cm × 30 cm, 75 cm × 35 cm and 75 cm × 40 cm. The experiment was laid out in a randomized complete block design with three replications.  Results revealed that variety and plant spacing had significant effect on the studied crop characters and yield. The highest plant height, highest number of leaves plant-1, longest cob, maximum diameter of cob, highest number of kernel cob-1, the highest 1000-grain weight, maximum grain yield and stover yield were observed in BARI hybrid maize 7. On the other hand, the shortest plant, lowest number of cob, diameter of cob, lowest number of grains cob-1, 1000-grain weight, grain yield and stover yield were observed in Khoi bhutta. The longest plant, highest cob, maximum diameter of cob, highest number of kernel cob-1 the highest 1000-grain weight, maximum grain yield and stover yield was observed in the spacing of 75 cm × 25 cm. In contrast, the spacing of 75 cm × 30 cm produced the lowest values of the above mentioned plant parameters and also showed the lowest grain yield. In regard to interaction effect of variety and spacing, the highest plant height (232.67 cm), maximum number of cob plant-1 (1.73), maximum diameter of cob (4.60 cm), highest number of kernel cob-1 (34), maximum stover yield (12.38 t ha-1) were observed at the spacing of 75 cm × 25 cm with BARI hybrid maize 7 and resulting in the highest grain yield (9.04 t ha-1). The lowest values of the above parameters were recorded in the narrowest plant spacing of 75 cm × 35 cm with Khoi bhutta. Based on the experimental results, it may be concluded that maize (cv. BARI hybrid maize 7) can be cultivated with a spacing of 75 cm × 25 cm for appreciable grain yield

Meteor Shower and Global Asset Allocation

We show that basic materials, financials, industrial, technologies, and telecommunication equity sectors were the primary exporters of volatility from the U.S. and that the magnitude of the spillover increased especially during and post-2008 financial crisis. Investing in low volatility spillover countries generate high Sharpe ratios for U.S. portfolio managers, especially during the financial crisis

Meteor shower and global asset allocation

Cross-market linkages allow transmission of shocks among markets. Previous measures of such spillovers are based on broader stock market indexes, which cannot identify the industries that are the principal drivers of spillovers and the industries that are most exposed to the spillovers. Using investable equity indexes, we show that basic materials, financials, industrials, technologies, and telecommunication equity sectors were the primary exporters of volatility from the U.S. and that the magnitude of the spillovers increased primarily during andpost-2008 financial crisis. There is evidence that Canada was most vulnerable to spillovers, while China’s exposure was the lowest among the countries in the sample. Based on the minimum variance portfolio optimization, we find that investing in foreign industries with low exposure to spillovers from the U.S. generates high Sharpe ratios for U.S. portfolio managers, especially during the financial crisis

Adverse Selection in Community Based Health Insurance among Informal Workers in Bangladesh: An EQ-5D Assessment

Community-based Health Insurance (CBHI) schemes are recommended for providing financial risk protection to low-income informal workers in Bangladesh. We assessed the problem of adverse selection in a pilot CBHI scheme in this context. In total, 1292 (646 insured and 646 uninsured) respondents were surveyed using the Bengali version of the EuroQuol-5 dimensions (EQ-5D) questionnaire for assessing their health status. The EQ-5D scores were estimated using available regional tariffs. Multiple logistic regression was applied for predicting the association between health status and CBHI scheme enrolment. A higher number of insured reported problems in mobility (7.3%; p = 0.002); self-care (7.1%; p = 0.000) and pain and discomfort (7.7%; p = 0.005) than uninsured. The average EQ-5D score was significantly lower among the insured (0.704) compared to the uninsured (0.749). The regression analysis showed that those who had a problem in mobility (m 1.25–2.17); self-care (OR = 2.29; 95% CI: 1.62–3.25) and pain and discomfort (OR = 1.43; 95% CI: 1.13–1.81) were more likely to join the scheme. Individuals with higher EQ-5D scores (OR = 0.46; 95% CI: 0.31–0.69) were less likely to enroll in the scheme. Given that adverse selection was evident in the pilot CBHI scheme, there should be consideration of this problem when planning scale-up of these kind of schemes

Seasonal variation in the coastal water phytoplankton communities and their environmental responses at upstream and downstream of the steep Naf River in the south-western Bay of Bengal

As a multinational river, the Naf River flows into the Bay of Bengal in the Indian Ocean, between the Cox's Bazar district of Bangladesh and the Rakhine state of Burma. In a multidisciplinary approach, several experiments were carried out to understand the seasonal diversity of the phytoplankton community structure. A total of four layers of water was sampled from four depths in the Naf River during monsoon (September) and winter (December) of 2016. 41 species of phytoplankton were identified, and 3 different dominant groups (Cyanobacteria, Diatoms, and Dinoflagellates) were found. Diatoms and cyanobacteria alone were found to be most prevalent. Higher species diversity was observed in the monsoon season, with Synedra sp. (1.84×105 cells L-1, 18.76%) and winter with Microcystis sp. (1.41×105 cells L-1, 17.74%), respectively. In monsoon, NO3-N and PO4-P were both higher than winter (450.9 and 34.4 µg L-1, respectively) especially, at downstream Naf River. Moreover, high diversity indexes (richness) of phytoplankton were recorded along with these estuarine stations. Significant correlations (P<0.01) of nutrients with phytoplankton may liable behind these scenarios. An analysis of principal component analysis (PCA) and linear regression supported this correspondence. In the monsoon season, the concentration of Chlorophyll-α reached the highest level (165 µg L-1) at a depth of 1.5 m, in Station-D. Cluster analysis based on the nutrient content of the Naf River was found two (upstream and downstream) mentionable zones during the winter and monsoon seasons. The results of the present study indicate that estuarine downstream areas are more productive than upstream areas of the Naf River at the southwest coastal zone of the Bay of Bengal

Older Adults' Mobility Amid COVID-19 Pandemic in Bangladesh: Safety and Perceived Risks of Using Public Transport

The COVID-19 pandemic is likely to have profound impact on the human activities including mobility and social life globally. Being most vulnerable to Covid-19, the older adults' risk perceptions and safety issues of using public and shared transport is likely to affect their modal choices. Based on 221 participants' responses through a unique online survey in Bangladesh, the study aims to assess older adults' mobility patterns pre and post-lockdown during COVID-19, and perceptions of risks and safety around transport post-lockdown. The results demonstrated that over 50% of respondents were unsure of their risks of contracting the virus. If contracted, 37% respondents felt it could be very critical for them. Only 13% respondents perceived little to no likelihood of contracting it. Non-motorized transport (NMT) modes such as walking and cycling were considered the safest to travel amid pandemic. There was substantial preference for private cars (67%) and rickshaws (54%) over shared modes of transport such as taxis, trains and buses. Older adults perceived that high risks are associated with activities such as using public toilets (92%) and going to a salon (80%), going to a hospital (86%), and fetching water from a public tap (62%). On the other hand, the three lowest-risk activities are going to the office (33%), essential grocery-shopping (19%) and walking as a form of exercise (only 3%). Besides public transport, improved walking infrastructures combined with increased public awareness on the risks of COVID-19 transmission are key to achieve sustainable urban mobility