Optimizing the total energy consumption and CO₂ emissions by distributing computational workload among worldwide dispersed data centers

Major internet service providers have built and are currently building the world's largest data centres (DCs), which has already resulted in significant global energy consumption. Energy saving measures, from chip to building level, have been introduced gradually in recent decades. However, there is further potential for savings by assessing the performance of different DCs on a wider scale and evaluating information technology (IT) workload distribution strategies among these DCs. This paper proposes a methodology to optimize the electricity consumption and CO2 emissions by distributing IT workload across multiple imaginary DCs. The DCs are modelled and controlled in a virtual test environment based on a building energy simulation (BES) tool (TRNSYS). A controller tool (Matlab) is used to support testing and tuning of the optimization algorithm. A case study, consisting of the distribution of IT workload across four different types of data centers in multiple locations with different climate conditions, is presented. The case study will illustrate.</p

Optimizing the total energy consumption and CO₂ emissions by distributing computational workload among worldwide dispersed data centers

Major internet service providers have built and are currently building the world's largest data centres (DCs), which has already resulted in significant global energy consumption. Energy saving measures, from chip to building level, have been introduced gradually in recent decades. However, there is further potential for savings by assessing the performance of different DCs on a wider scale and evaluating information technology (IT) workload distribution strategies among these DCs. This paper proposes a methodology to optimize the electricity consumption and CO2 emissions by distributing IT workload across multiple imaginary DCs. The DCs are modelled and controlled in a virtual test environment based on a building energy simulation (BES) tool (TRNSYS). A controller tool (Matlab) is used to support testing and tuning of the optimization algorithm. A case study, consisting of the distribution of IT workload across four different types of data centers in multiple locations with different climate conditions, is presented. The case study will illustrate.</p

Stress and stressors of medical student near-peer tutors during courses: a psychophysiological mixed methods study

Background: Structured peer-led tutorial courses are widespread and indispensable teaching methods that relieve teaching staff and contribute to the development of students’ competencies. Nevertheless, despite high general stress levels in medical students and associated increases in psychopathology, specific knowledge of peer tutors’ additional burdens is very limited. Methods: Sixty student near-peer tutors from two structured peer-teaching programmes volunteered to participate. On multiple occasions in three different course sessions, we assessed tutors’ subjective stress, affective state, heart rate variability, and salivary cortisol. Additionally, tutors named everyday and course-specific stressors, which were evaluated by means of content analyses. Results: The study participation rate was high (63% of all active tutors). The participating tutors are socially well adapted and resilient individuals. They report a variety of stressors such as time pressure, participant characteristics, teacher role demands, and study requirements, but nevertheless display only moderate psychological and physiological stress that decreases over sessions. Tutors’ negative affect in sessions is low; their positive affect is consistently high for senior as well as novice tutors. Tutors rate their courses’ quality as high and quickly recover after sessions. Conclusions: Tutors successfully cope with teaching-associated and everyday life demands. The results corroborate the viability and success of current peer-teaching programmes from the tutors’ perspective. This study is the first to comprehensively quantify tutors’ stress and describe frequent stressors, thus contributing to the development of better peer teaching programmes and tutor qualification training

Mentale Gehalte und erweiterter Geist: Warum das Argument der Nichtabgeleitetheit scheitert

Hundertmark F. Mentale Gehalte und erweiterter Geist: Warum das Argument der Nichtabgeleitetheit scheitert. In: Michel JG, Boström KJ, Pohl M, eds. Ist der Geist im Kopf?: Beiträge zur These des erweiterten Geistes. Münster: mentis; 2016: 133-160.Der These des erweiterten Geistes zufolge befinden sich manche mentalen Repräsentationen außerhalb der körperlichen Grenzen der Wesen, zu denen sie gehören. Einer der stärksten Einwände gegen diese These stellt das Argument der Nichtabgeleitetheit von Frederick Adams, Ken Aizawa und Jerry Fodor dar. Dieses Argument setzt voraus, dass genuine mentale Repräsentationen nichtabgeleitete Gehalte haben – ihre semantischen Eigenschaften sind also nicht durch Absichten, Wünsche oder Konventionen konstituiert. Repräsentationen mit nichtabgeleitetem Gehalt finden sich jedoch, so das Argument weiter, nur innerhalb der körperlichen Grenzen mentaler Wesen. Ich werde dafür argumentieren, dass das Argument der Nichtabgeleitetheit scheitert, da es insbesondere bei Tieren externe Repräsentationen gibt, deren Gehalt nichtabgeleitet ist. Dies folgt jedenfalls aus der aussichtsreichsten Theorie nichtabgeleiteter Repräsentationen, der Teleosemantik, und es gibt gute Gründe anzunehmen, dass auch andere naturalistische Gehaltstheorien dieselbe Implikation haben

Promoting medical competencies through a didactic tutor qualification programme – a qualitative study based on the CanMEDS Physician Competency Framework

Background: In peer-led tutorial courses, qualified medical students (“tutors”) provide their peers with opportunities to deepen their theoretical knowledge effectively and to practice clinical skills already in preclinical semesters. At the Medical Faculty of Heidelberg University, a structured medical didactic qualification programme prepares and trains future tutors for their responsibilities. This programme consists of four modules: 1. medical didactics and group leadership, 2. subject-specific training, 3. performance of tutorial courses as well as 4. collegial advice and reflection on the tutors’ activities. The aim of this study is to systematically analyse and present the development of role competencies for medical tutors based on the CanMEDS Physician Competency Framework through the didactic qualification programme. Methods: We applied a qualitative research approach to detect CanMEDS role competencies acquisition within the tutor qualification programme. The CanMEDS framework describes key competencies, grouped thematically under seven professional roles. Two tutors and three training coordinators independently assigned the individual modules of the tutor qualification programme to the key competencies of the CanMEDS framework. Tutors and training coordinators compared and discussed the allocations within the groups in a consensus finding process. All authors analysed the findings in order to find out the so-called “hidden curriculum”. The views of both groups are presented separately. Results: The training programme promotes the acquisition of competencies in all seven CanMEDS roles. The roles of the scholar and the leader are promoted in all modules. In addition, the first and fourth module focus predominately on the role of the collaborator, the second on the role of the medical expert and communicator, and the fourth on the role of the professional. Conclusions: The systematic analysis through assignment of the CanMEDS roles to the individual modules of the tutor qualification programme documents the comprehensive acquisition of competencies, not only with regard to the tutor activity, but generally with regard to the later role of the physician. The reflection on one’s own competency acquisition can support the promotion of corresponding competencies in the qualification programme and their transfer into the professional practice later

MOA-2019-BLG-008Lb : a new microlensing detection of an object at the planet/brown dwarf boundary

Funding: R.A.S. and E.B. gratefully acknowledge support from NASA grant 80NSSC19K0291. Y.T. and J.W. acknowledge the support of DFG priority program SPP 1992 “Exploring the Diversity of Extrasolar Planets” (WA 1047/11-1). K.H. acknowledges support from STFC grant ST/R000824/1. J.C.Y. acknowledges support from NSF grant No. AST-2108414. Work by C.H. was supported by the grants of the National Research Foundation of Korea (2019R1A2C2085965 and 2020R1A4A2002885). D.M.B. acknowledges the support of the NYU Abu Dhabi Research Enhancement Fund under grant RE124. This work was partly supported by the National Science Foundation of China (grant Nos. 11333003, 11390372, and 11761131004 to S.M.). The MOA project is supported by JSPS KAKENHI grant Nos. JSPS24253004, JSPS26247023, JSPS23340064, JSPS15H00781, JP16H06287, and JP17H02871.We report on the observations, analysis and interpretation of the microlensing event MOA-2019-BLG-008. The observed anomaly in the photometric light curve is best described through a binary lens model. In this model, the source did not cross caustics and no finite-source effects were observed. Therefore, the angular Einstein ring radius θE cannot be measured from the light curve alone. However, the large event duration, tE ∼ 80 days, allows a precise measurement of the microlensing parallax πE. In addition to the constraints on the angular radius θ* and the apparent brightness Is of the source, we employ the Besançon and GalMod galactic models to estimate the physical properties of the lens. We find excellent agreement between the predictions of the two galactic models: the companion is likely a resident of the brown dwarf desert with a mass Mp ∼ 30 MJup, and the host is a main-sequence dwarf star. The lens lies along the line of sight to the Galactic bulge, at a distance of ≤4 kpc. We estimate that in about 10 yr the lens and source will be separated by ∼55 mas, and it will be possible to confirm the exact nature of the lensing system by using high-resolution imaging from ground- or space-based observatories.Publisher PDFPeer reviewe

OGLE-2018-BLG-0799Lb: a Sub-Saturn-Mass Planet Orbiting a Very Low Mass Dwarf

We report the discovery and analysis of a sub-Saturn-mass planet in the microlensing event OGLE-2018-BLG-0799. The planetary signal was observed by several ground-based telescopes, and the planet-host mass ratio is q = (2.65±0.16)×10⁻³. The ground-based observations yield a constraint on the angular Einstein radius θ_E, and the microlens parallax π_E is measured from the joint analysis of the Spitzer and ground-based observations, which suggests that the host star is most likely to be a very low-mass dwarf. A full Bayesian analysis using a Galactic model indicates that the planetary system is composed of an M_(planet) = 0.22^(+0.19)_(−0.06) M_J planet orbiting an M_(host) = 0.080^(+0.080)_(−0.020) M⊙, at a distance of D_L = 4.42^(+1.73)_(−1.23) kpc. The projected planet-host separation is r⊥ = 1.27^(+0.45)_(−0.29) AU, implying that the planet is located beyond the snowline of the host star. However, because of systematics in the Spitzer photometry, there is ambiguity in the parallax measurement, so the system could be more massive and farther away

OGLE-2019-BLG-0825: Constraints on the Source System and Effect on Binary-lens Parameters arising from a Five Day Xallarap Effect in a Candidate Planetary Microlensing Event

We present an analysis of microlensing event OGLE-2019-BLG-0825. This event was identified as a planetary candidate by preliminary modeling. We find that significant residuals from the best-fit static binary-lens model exist and a xallarap effect can fit the residuals very well and significantly improves $\chi^2$ values. On the other hand, by including the xallarap effect in our models, we find that binary-lens parameters like mass-ratio, $q$, and separation, $s$, cannot be constrained well. However, we also find that the parameters for the source system like the orbital period and semi major axis are consistent between all the models we analyzed. We therefore constrain the properties of the source system better than the properties of the lens system. The source system comprises a G-type main-sequence star orbited by a brown dwarf with a period of $P\sim5$ days. This analysis is the first to demonstrate that the xallarap effect does affect binary-lens parameters in planetary events. It would not be common for the presence or absence of the xallarap effect to affect lens parameters in events with long orbital periods of the source system or events with transits to caustics, but in other cases, such as this event, the xallarap effect can affect binary-lens parameters.Comment: 19 pages, 7 figures, 6 tables. Accepted by A

<i>Spitzer</i> Microlensing Parallax Reveals Two Isolated Stars in the Galactic Bulge

We report the mass and distance measurements of two single-lens events from the 2017 $\textit {Spitzer}$ microlensing campaign. The ground-based observations yield the detection of finite-source effects, and the microlens parallaxes are derived from the joint analysis of ground-based observations and $\textit {Spitzer}$ observations. We find that the lens of OGLE-2017-BLG-1254 is a 0.60 ± 0.03 M ⊙ star with D LS = 0.53 ± 0.11 kpc, where D LS is the distance between the lens and the source. The second event, OGLE-2017-BLG-1161, is subject to the known satellite parallax degeneracy, and thus is either a ${0.51}_{-0.10}^{+0.12}\,{M}_{\odot }$ star with D LS = 0.40 ± 0.12 kpc or a ${0.38}_{-0.12}^{+0.13}\,{M}_{\odot }$ star with D LS = 0.53 ± 0.19 kpc. Both of the lenses are therefore isolated stars in the Galactic bulge. By comparing the mass and distance distributions of the eight published $\textit {Spitzer}$ finite-source events with the expectations from a Galactic model, we find that the $\textit {Spitzer}$ sample is in agreement with the probability of finite-source effects occurring in single-lens events