Installing, Running and Maintaining Large Linux Clusters at CERN

Having built up Linux clusters to more than 1000 nodes over the past five years, we already have practical experience confronting some of the LHC scale computing challenges: scalability, automation, hardware diversity, security, and rolling OS upgrades. This paper describes the tools and processes we have implemented, working in close collaboration with the EDG project [1], especially with the WP4 subtask, to improve the manageability of our clusters, in particular in the areas of system installation, configuration, and monitoring. In addition to the purely technical issues, providing shared interactive and batch services which can adapt to meet the diverse and changing requirements of our users is a significant challenge. We describe the developments and tuning that we have introduced on our LSF based systems to maximise both responsiveness to users and overall system utilisation. Finally, this paper will describe the problems we are facing in enlarging our heterogeneous Linux clusters, the progress we have made in dealing with the current issues and the steps we are taking to gridify the clustersComment: 5 pages, Proceedings for the CHEP 2003 conference, La Jolla, California, March 24 - 28, 200

A new CP-approach for a parallel machine scheduling problem with time constraints on machine qualifications

International audienceThis paper considers the scheduling of job families on parallel machines with time constraints on machine qualifications. In this problem, each job belongs to a family and a family can only be executed on a subset of qualified machines. In addition, machines can lose their qualifications during the schedule. Indeed, if no job of a family is scheduled on a machine during a given amount of time, the machine loses its qualification for this family. The goal is to minimize the sum of job completion times, i.e. the flow time, while maximizing the number of qualifications at the end of the schedule. The paper presents a new Constraint Programming (CP) model taking more advantages of the CP feature to model machine disqualifications. This model is compared with two existing models: an Integer Linear Programming (ILP) model and a Constraint Programming model. The experiments show that the new CP model outperforms the other model when the priority is given to the number of disqualifications objective. Furthermore, it is competitive with the other model when the flow time objective is prioritized

Аналіз ефективності реалізації арифметичних алгоритмів на мовах програмування C++ та Python

У даній роботі представлені результати обчислювального експерименту, метою якого є уточнення реальної швидкодії арифметич-них алгоритмів з використанням арифметики довільної точності при реалізації на мовах програмування C++ та Python. Як матема-тичну модель для арифметичних алгоритмів обрана цілочисельна «машина, що складає». «Машина, що складає» – це математична абстракція, введена Р. Флойдом та Д. Кнутом, суть якої полягає у тому, що лише за допомогою операцій додавання, віднімання, порівняння, присвоювання та обмеженої кількості регістрів можна з прийнятною обчислювальною ефективністю виразити більш складні операції, такі як знаходження лишку за модулем, множення, знаходження найбільшого спільного дільника, піднесення до степеня за модулем. Особливістю даної реалізації є використання арифметики довільної точності, що може бути корисним для ви-користання у криптографічних алгоритмах.В данной работе представлены результаты вычислительного эксперимента, целью которого является уточнение реальной производительности арифметических алгоритмов с использованием арифметики произвольной точности при реализации на языках программирования C++ и Python. Как математическая модель для арифметических алгоритмов выбрана целочисленная «складывающая машина». «Складывающая машина» – это математическая абстракция, введённая Р. Флойдом и Д. Кнутом, суть которой заключается в том, что с помощью только операций сложения, вычитания, сравнения, присваивания и ограниченного количества регистров можно с приемлемой вычислительной эффективностью выразить более сложные операции, такие как нахождение остатка по модулю, умножение, нахождение наибольшего общего делителя, возведение в степень по модулю. Особенностью данной реализации является использование арифметики произвольной точности, что может быть полезным для использования в криптографических алгоритмах.This paper presents the results of the numerical experiment, which aims to clarify the actual performance of arithmetic algorithms implemented in C ++ and Python programming languages using arbitrary precision arithmetic. "Addition machine" has been chosen as a mathematical model for integer arithmetic algorithms. "Addition machine" is a mathematical abstraction, introduced by R. Floyd and D. Knuth. The essence of "addition machine" is the following: using only operations of addition, subtraction, comparison, assignment and a limited number of registers it is possible to calculate more complex operations such as finding the residue modulo, multiplication, finding the greatest common divisor, exponentiation modulo with reasonable computational efficiency. One of the features of this implementation is the use of arbitrary precision arithmetic, which may be useful in cryptographic algorithms

Nurses\u27 Alumnae Association Bulletin - Volume 7 Number 11

Anna M. Shafer Barton Memorial Division Births Changes in the Ophthalmology Division Change of Address Clara Melville Fund Continental Tour Deceased Digest of Meetings Inter-County Hospitalization Plan Katherine Childs\u27 Letter Lost Members Marriages Miscellaneous Nursing Home Committee\u27s Report Physical Advantages President James L. Kauffman\u27s Letter President\u27s Greeting Private Duty Section Prizes Relief Fund School Nursing Silhouette of a Public Health Nurse Rooming-in of Infant with Mother Staff Activities The Student White Haven Divisio

Kenneth Holmberg from VTT Technical Research Centre of Finland Ltd won the highest international award in the tribology field

On 20 December, the Tribology Trust presented VTT's Kenneth Holmberg with the most highly prized award in the field, the Tribology Gold Medal Award, for his long-standing, major achievements in material and friction research. The award was presented by Her Majesty’s Ambassador to Finland in a ceremony at the British Embassy in Helsinki on 20 December 2017

Estimates of mobility for prediction of structure-borne sound transmission in buildings

This paper aims to provide a practical approach to the prediction of structure-borne sound power of mechanical installations in buildings. For structure-borne power, two source quantities, activity and mobility, are required, in combination with one receiver quantity, the receiver mobility. The source activity, in the form of free velocity or blocked force, is usually measured. For source mobility and receiver mobility, estimates, based on simple expressions, can provide a useful starting point. Also, machine bases may be categorised as: compact, plate-like, flanged or framed. Receiver structures, floors and walls, may be categorised as: plate-like, ribbed plate or framed plate. The estimates of source mobility are based on the rigid body value, the characteristic plate mobility and the fundamental plate frequency. For ribbed and framed plate structures, the mobility will vary with location, but again simple estimates of mobility, based on characteristic values and distance from the ribs, are possible