Strong positivity for quantum theta bases of quantum cluster algebras

We construct “quantum theta bases,” extending the set of quantum cluster monomials, for various versions of skew-symmetric quantum cluster algebras. These bases consist precisely of the indecomposable universally positive elements of the algebras they generate, and the structure constants for their multiplication are Laurent polynomials in the quantum parameter with non-negative integer coefficients, proving the quantum strong cluster positivity conjecture for these algebras. The classical limits recover the theta bases considered by Gross–Hacking–Keel–Kontsevich (J Am Math Soc 31(2):497–608, 2018). Our approach combines the scattering diagram techniques used in loc. cit. with the Donaldson–Thomas theory of quivers.

Optimizing Data Intensive Flows for Networks on Chips

A novel framework is proposed to find efficient data intensive flow distributions on Networks on Chip (NoC). Voronoi diagram techniques are used to divide a NoC array of homogeneous processors and links into clusters. A new mathematical tool, named the flow matrix, is proposed to find the optimal flow distribution for individual clusters. Individual flow distributions on clusters are reconciled to be more evenly distributed. This leads to an efficient makespan and a significant savings in the number of cores actually used. The approach here is described in terms of a mesh interconnection but is suitable for other interconnection topologies.

What do Computer Games have to do with Libraries and Learning?

Two teachers have undertaken a project in which year five and six students design computer games and year ten to twelve students build them. The younger students are taught basic flow diagram techniques and thus patterns of logic. They then select a topic of personal interest for their game design. The game is in the form of a quest for the player and must contain material that has been researched using Library resources. The complete, fully documented game designs are passed to the senior Information Technology students who produce them. All students are fully and formally accredited for their work.

Three Approaches to Low-Duty Turbo Compressor Efficiency Exploitation Evaluation

This paper presents three approaches for isentropic, energy, and exergy evaluations of a low-duty liquid natural gas (LNG) vapor turbo compressor during exploitation on a conventional LNG carrier. The evaluation was conducted on the measured performance parameters under 22 various turbo compressor operating regimes. The turbo compressor performance was evaluated in the temperature span from −69 to −105 °C and during changes in the rpm of the main propulsion turbine and, consequently, the main boiler load. The results show that the highest measured turbo compressor isentropic efficiency is in agreement with the manufacturer specifications, equaling 75.23% at a main propulsion turbine rpm of 53.5. At the highest measured loads and rpm, the turbo compressor energy and exergy efficiencies reach the highest values of 57.81% and 28.51%, respectively. In each observed operating regime, the influence of the ambient temperature change on the turbo compressor exergy efficiency was investigated. At the lowest and the highest measured loads, turbo compressor energy and exergy flow streams are presented in a Sankey diagram. Techniques for cargo temperature maintenance during the ship voyage are presented, as the results show that low suction gas temperatures influence turbo compressor efficiency.

PERENCANAAN PENJADWALAN TENAGA KERJA PADA UKM SONGKOK IKAT KEPALA

Songkok Ikat Kepala was one of UKM which produce songkok in Gresik. This UKM Songkok Ikat Kepala was produced by strategy “make to order” and there was no guideline for period production. Problems that occurred were known asdelayed production process at the process of sewing. The aim of this study was (1) to analyze the planning of labor scheduling and (2) to determine the standard of estimation of item production process. The data were analyzed by using period study and gantt diagram techniques. The results of the study showed that there were 2 standards of estimation, those are fast and low standards. Fast standard needed the work estimation in 444 seconds. However, low standard needed the work estimation in 536 seconds. Therefore, this study was expected to be guidance to arrange the schedule by using gantt diagram.