Locally Optimal Load Balancing

This work studies distributed algorithms for locally optimal load-balancing: We are given a graph of maximum degree $\Delta$, and each node has up to $L$ units of load. The task is to distribute the load more evenly so that the loads of adjacent nodes differ by at most $1$. If the graph is a path ($\Delta = 2$), it is easy to solve the fractional version of the problem in $O(L)$ communication rounds, independently of the number of nodes. We show that this is tight, and we show that it is possible to solve also the discrete version of the problem in $O(L)$ rounds in paths. For the general case ($\Delta > 2$), we show that fractional load balancing can be solved in $\operatorname{poly}(L,\Delta)$ rounds and discrete load balancing in $f(L,\Delta)$ rounds for some function $f$, independently of the number of nodes.Comment: 19 pages, 11 figure

Reusable Ionogel-based Photo-actuators in a Lab-on-a-disc

This paper describes the design, fabrication and performance of a reusable ionogel-based photo-actuator, in-situ photopolymerised into a lab-on-a-disc microfluidic device, for flow control. The ionogel provides an effective barrier to liquids during storage of reagents and spinning of the disc. A simple LED (white light) triggers actuation of the ionogel for selective and precise channel opening at a desired location and time. The mechanism of actuation is reversible, and regeneration of the actuator is possible with an acid chloride solution. In order to achieve regeneration, the Lab-on-a-Disc device was designed with a microchannel connected perpendicularly to the bottom of the ionogel actuator (regeneration channel). This configuration allows the acid solution to reach the actuator, independently from the main channel, which initiates ionogel swelling and main channel closure, and thereby enables reusability of the whole device.Economía y Competitividad), Spain. This project has receivedfunding from the European Union Seventh Framework Programme(FP7) for Research, Technological Development and Demonstrationunder grant agreement no. 604241. JS and FBL acknowledge fund-ing support from Gobierno de Espa˜na, Ministerio de Economía yCompetitividad, with Grant No. BIO2016-80417-P and personallyacknowledge to Marian M. De Pancorbo for letting them to use herlaboratory facilities at UPV/EHU. A.T., L.F., and D.D. are grateful forfinancial support from the Marie Curie Innovative Training Net-work OrgBIO (Marie Curie ITN, GA607896) and Science FoundationIreland (SFI) under the Insight Centre for Data Analytics initiative,Grant Number SFI/12/RC/2289

A load-sharing architecture for high performance optimistic simulations on multi-core machines

In Parallel Discrete Event Simulation (PDES), the simulation model is partitioned into a set of distinct Logical Processes (LPs) which are allowed to concurrently execute simulation events. In this work we present an innovative approach to load-sharing on multi-core/multiprocessor machines, targeted at the optimistic PDES paradigm, where LPs are speculatively allowed to process simulation events with no preventive verification of causal consistency, and actual consistency violations (if any) are recovered via rollback techniques. In our approach, each simulation kernel instance, in charge of hosting and executing a specific set of LPs, runs a set of worker threads, which can be dynamically activated/deactivated on the basis of a distributed algorithm. The latter relies in turn on an analytical model that provides indications on how to reassign processor/core usage across the kernels in order to handle the simulation workload as efficiently as possible. We also present a real implementation of our load-sharing architecture within the ROme OpTimistic Simulator (ROOT-Sim), namely an open-source C-based simulation platform implemented according to the PDES paradigm and the optimistic synchronization approach. Experimental results for an assessment of the validity of our proposal are presented as well

Simple Load Balancing for Distributed Hash Tables

Distributed hash tables have recently become a useful building block for a variety of distributed applications. However, current schemes based upon consistent hashing require both considerable implementation complexity and substantial storage overhead to achieve desired load balancing goals. We argue in this paper that these goals can b e achieved more simply and more cost-effectively. First, we suggest the direct application of the "power of two choices" paradigm, whereby an item is stored at the less loaded of two (or more) random alternatives. We then consider how associating a small constant number of hash values with a key can naturally b e extended to support other load balancing methods, including load-stealing or load-shedding schemes, as well as providing natural fault-tolerance mechanisms

Load-independent characterization of trade-off fronts for operational amplifiers

Abstract—In emerging design methodologies for analog integrated circuits, the use of performance trade-off fronts, also known as Pareto fronts, is a keystone to overcome the limitations of the traditional top-down methodologies. However, most techniques reported so far to generate the front neglect the effect of the surrounding circuitry (such as the output load impedance) on the Pareto-front, thereby making it only valid for the context where the front was generated. This strongly limits its use in hierarchical analog synthesis because of the heavy dependence of key performances on the surrounding circuitry, but, more importantly, because this circuitry remains unknown until the synthesis process. We will address this problem by proposing a new technique to generate the trade-off fronts that is independent of the load that the circuit has to drive. This idea is exploited for a commonly used circuit, the operational amplifier, and experimental results show that this is a promising approach to solve the issue

Assessing load-sharing within optimistic simulation platforms

The advent of multi-core machines has lead to the need for revising the architecture of modern simulation platforms. One recent proposal we made attempted to explore the viability of load-sharing for optimistic simulators run on top of these types of machines. In this article, we provide an extensive experimental study for an assessment of the effects on run-time dynamics by a load-sharing architecture that has been implemented within the ROOT-Sim package, namely an open source simulation platform adhering to the optimistic synchronization paradigm. This experimental study is essentially aimed at evaluating possible sources of overheads when supporting load-sharing. It has been based on differentiated workloads allowing us to generate different execution profiles in terms of, e.g., granularity/locality of the simulation events. © 2012 IEEE

Cognitive Load and Its Relationship with Mental Capacity in Accordance with Their Levels at Students of the Secondary Stage in Terms of Sweller Theory

The study aimed to identify the cognitive load and its relationshipwith mental capacity in accordance their levels at the students of the secondary stage in the terms of Sweller theory. The study sample consisted of (300) male and female eleventh and twelfth grade students from the leadership schools in Amman. The researcher used the cognitive load scale and the mental capacity scale.The results showed a high level of cognitive load in male and female, a high cognitive Load on students of scientific specialization rather than literary specialization, and that the mental capacity of the study sample in general is moderate, and that the mental capacity of students of scientific specialization is high compared to the mental capacity of students of literary specialization. In addition, that the association between higher mental capacity and cognitive load was higher in males than in females, and that the relationship between the mean mental capacity of both sexes with the cognitive load was statistically significant

ANFIS Modeling of Dynamic Load Balancing in LTE

Modelling of ill-defined or unpredictable systems can be very challenging. Most models have relied on conventional mathematical models which does not adequately track some of the multifaceted challenges of such a system. Load balancing, which is a self-optimization operation of Self-Organizing Networks (SON), aims at ensuring an equitable distribution of users in the network. This translates into better user satisfaction and a more efficient use of network resources. Several methods for load balancing have been proposed. While some of them have a very buoyant theoretical basis, they are not practical. Furthermore, most of the techniques proposed the use of an iterative algorithm, which in itself is not computationally efficient as it does not take the unpredictable fluctuation of network load into consideration. This chapter proposes the use of soft computing, precisely Adaptive Neuro-Fuzzy Inference System (ANFIS) model, for dynamic QoS aware load balancing in 3GPP LTE. The use of ANFIS offers learning capability of neural network and knowledge representation of fuzzy logic for a load balancing solution that is cost effective and closer to human intuition. Three key load parameters (number of satisfied user in the net- work, virtual load of the serving eNodeB, and the overall state of the target eNodeB) are used to adjust the hysteresis value for load balancing

Five Total Maximum Daily Loads for Indicator Bacteria in Four Austin Streams

The report provides an overview of Waller Creek as well as detailed information about land use, flow duration, and TMDL of bacteria.EXECUTIVE SUMMARY: This document describes total maximum daily loads (TMDLs) for four Austin streams and their tributaries in which concentrations of indicator bacteria exceed the criteria used to evaluate attainment of the contact recreation use. The Texas Commission on Environmental Quality (TCEQ) first identified the impairments to the Spicewood Tributary to Shoal Creek (Segment 1403J) and Taylor Slough South (1403K) in the 2002 State of Texas Clean Water Act Section 303(d) List (TCEQ, 2002), adding Waller Creek (1429C) and Walnut Creek (1428B) when the list was updated in 2006. The impaired segments and corresponding assessment units (AUs) are: Spicewood Tributary to Shoal Creek (1403J_01); ? Taylor Slough South (1403K_01); ? Walnut Creek (1428B_05); ? Waller Creek (1429C_02, 1429C_03); Together these four freshwater streams total approximately 31.6 miles in length with watersheds covering 63.465 square miles. They are almost entirely within the City of Austin full purpose, planning, or exterritorial jurisdiction. They are almost entirely within Travis County, except that the Walnut Creek watershed includes a very small portion of Williamson County. Currently, there are not any permitted domestic wastewater discharges within the watersheds of any of these streams. The Walnut Creek Wastewater Treatment Facility (WWTF), operated by the City of Austin, discharges its effluent directly into the Colorado River instead of Walnut Creek. There are not any permitted industrial bacteria discharges within the watersheds. The Freescale Semiconductor WWTF only discharges bacteria-free process water. The primary loads are from various nonpoint sources that enter the streams via stormwater. The Spicewood Tributary to Shoal Creek is an intermittent freshwater stream approximately 1.4 mile in length from MOPAC/Loop-1 upstream to its headwaters near Spicewood Springs Road and Mesa Drive. The watershed is about 0.650 square miles and is entirely located in the City of Austin. There are no regulated wastewater discharges within this watershed. Taylor Slough South is a perennial freshwater stream approximately 1.1 mile in length from Lake Austin upstream to its headwaters near West 35th Street and MOPAC/Loop-1. The watershed is 0.650 square miles and is entirely located in the City of Austin. There are no regulated wastewater discharges within this watershed. Waller Creek is a perennial freshwater stream approximately 6.7 miles in length from its confluence with Lady Bird Lake upstream to its headwaters near Northcrest Boulevard and West St. Johns Avenue. The watershed is 5.648 square miles and is entirely located in the City of Austin. There are no regulated domestic wastewater discharges within this watershed. Walnut Creek is a perennial freshwater stream approximately 22.4 miles in length from its confluence with the Colorado River upstream to its headwaters near McNeil Drive and Parmer Lane. The watershed is approximately 56.517 square miles and is mostly in the City of Austin full purpose jurisdiction. However portions are in the planning, or exterritorial jurisdictions. Currently, there is only one industrial wastewater discharge located within its watershed, the Freescale Semiconductor plant, which only discharges bacteria-free process water into Walnut Creek AU 1428B_01. Escherichia coli (E. coli) are the preferred indicator bacteria for assessing the contact recreation use in freshwater, and were used for development of the TMDLs, with one exception. Fecal coliform bacteria were used for assessment of Walnut Creek AU 1428B_02 because it was the standard when data were collected in 1999. E. coli data are not currently available, but will be collected in the future. The criteria for assessing attainment of the contact recreation use are expressed as the number (or “counts”) of bacteria. The primary contact recreation use is not supported when the geometric mean of E. coli samples exceeds 126 most probable number (MPN) per 100 milliliters (mL), or the geometric mean of fecal coliform samples exceeds 200 MPN per 100 mL. For the 2012 assessment period, the geometric means of all AUs examined exceeded 126 MPN/100 mL E. coli or 200 MPN/100 mL fecal coliform, indicating non-support of primary contact recreation. Possible sources of indicator bacteria within the watersheds of the impaired AUs are stormwater runoff from regulated storm sewers, illicit discharges from storm sewers, sanitary sewer overflows (SSOs), and unregulated sources such as wildlife, unmanaged feral animals, and pets. Load duration curve (LDC) analyses of instream flows were used to estimate allowable pollutant loads and specific TMDL allocations. Because bacteria loads are usually highest at high flow, the very high flow regime was used as the critical flow for determining the TMDL. Predictions of future growth of existing or new domestic point sources were not necessary. The City of Austin has informed TCEQ that it intends to accommodate all growth with its central wastewater treatment system, which discharges directly into the Colorado River instead of these watersheds. The wasteload allocation (WLA) for regulated stormwater was based on the percentage of each watershed regulated under a Phase I or Phase II Texas Pollutant Discharge Elimination System (TPDES) stormwater permit. Compliance with these TMDLs is based on keeping indicator bacteria concentrations in the selected waters below the geometric mean criterion of E. coli less than 126 MPN/100 mL or fecal coliform less than 200 MPN/100 mL.Waller Creek Working Grou

Quasirandom Load Balancing

We propose a simple distributed algorithm for balancing indivisible tokens on graphs. The algorithm is completely deterministic, though it tries to imitate (and enhance) a random algorithm by keeping the accumulated rounding errors as small as possible. Our new algorithm surprisingly closely approximates the idealized process (where the tokens are divisible) on important network topologies. On d-dimensional torus graphs with n nodes it deviates from the idealized process only by an additive constant. In contrast to that, the randomized rounding approach of Friedrich and Sauerwald (2009) can deviate up to Omega(polylog(n)) and the deterministic algorithm of Rabani, Sinclair and Wanka (1998) has a deviation of Omega(n^{1/d}). This makes our quasirandom algorithm the first known algorithm for this setting which is optimal both in time and achieved smoothness. We further show that also on the hypercube our algorithm has a smaller deviation from the idealized process than the previous algorithms.Comment: 25 page