Parallel scheduling of multiclass M/M/m queues: Approximate and heavy-traffic optimization of achievable performance

We address the problem of scheduling a multiclass $M/M/m$ queue with Bernoulli feedback on $m$ parallel servers to minimize time-average linear holding costs. We analyze the performance of a heuristic priority-index rule, which extends Klimov's optimal solution to the single-server case: servers select preemptively customers with larger Klimov indices. We present closed-form suboptimality bounds (approximate optimality) for Klimov's rule, which imply that its suboptimality gap is uniformly bounded above with respect to (i) external arrival rates, as long as they stay within system capacity;and (ii) the number of servers. It follows that its relativesuboptimality gap vanishes in a heavy-traffic limit, as external arrival rates approach system capacity (heavy-traffic optimality). We obtain simpler expressions for the special no-feedback case, where the heuristic reduces to the classical $c \mu$ rule. Our analysis is based on comparing the expected cost of Klimov's ruleto the value of a strong linear programming (LP) relaxation of the system's region of achievable performance of mean queue lengths. In order to obtain this relaxation, we derive and exploit a new set ofwork decomposition laws for the parallel-server system. We further report on the results of a computational study on the quality of the $c \mu$ rule for parallel scheduling.

Évaluation statistique des résultats des analyses ADN de 2005 à 2011 et recommandations stratégiques au sein de la section d'Identité judiciaire de la Police cantonale vaudoise

Notre étude a eu pour but d'analyser les résultats des analyses ADN effectuées sur les traces relevées sur des scènes de crimes ou sur des objets s'y apparentant. Cette analyse nous a permis d'en identifier les points forts et les points faibles. Les données concernant les résultats ADN des années 2005 à 2008 dans le canton de Vaud ont montré une augmentation significative du nombre de traces envoyées, avec en parallèle un déclin de la qualité des résultats. Suite à cette observation, des solutions ayant pour but de réduire le nombre de ces analyses négatives ont dû être adoptées. Des changements opérationnels ont alors été mis en place dès 2009. Il s'agissait alors, d'une part, d'agir au niveau des traces de contact en tenant compte du type de support sur lequel la trace était prélevée, et, d'autre part, d'agir sur les traces riches (sang, salive, sperme) en mettant en place l'analyse systématique de la nature de la trace à l'aide de tests indicatifs. L'évaluation des conséquences de la mise en place de ces procédures a été possible à l'aide d'une nouvelle analyse statistique. Les résultats montrent qu'un meilleur tri des traces permet une amélioration des résultats.

CrossRoads, Spring/Summer 2005; quarterly publication of the Governor's Traffic Safety Bureau, Iowa Department of Public Safety

Quarterly publication of the Governor's Traffic Safety Bureau, Iowa Department of Public Safety containing traffic safety and related information and news articles

CrossRoads, Autumn 2006; quarterly publication of the Governor's Traffic Safety Bureau, Iowa Department of Public Safety

Quarterly publication of the Governor's Traffic Safety Bureau, Iowa Department of Public Safety containing traffic safety and related information and news articles

Management of major accidents with on-site 144 dispatcher

Introduction: An excellent coordination between firefighters, policemen and medical rescue is the key to success in the management of major accidents. In order to improve and assist the medical teams engaged on site, the Swiss "medical command and control system" for rescue operations is based on a binomial set up involving one head emergency doctor and one head rescue paramedic, both trained in disaster medicine. We have recently experimented an innovative on-site "medical command and control system", based on the binomial team, supported by a dedicated 144 dispatcher. Methods: A major road traffic accident took place on the highway between Lausanne and Vevey on April 9th 2008. We have retrospectively collected all data concerning the victims as well as the logistics and dedicated structures, reported by the 144, the Hospitals, the Authority of the State and the Police and Fire Departments. Results: The 72-car pileup caused one death and 26 slightly injured patients. The management on the accident site was organized around a tripartite system, gathering together the medical command and control team with the police and fire departments. On the medical side, 16 ambulances, 2 medical response teams (SMUR), the Rega crew and the medical command and control team were dispatched by the 144. On that occasion an advanced medical command car equipped with communication devices and staffed with a 144 dispatcher was also engaged, allowing efficient medical regulation directly from the site. Discussion: The specific skills of one doctor and one paramedic both trained for disaster's management proved to be perfectly complementary. The presence of a dispatcher on site with a medical command car also proved to be useful, improving orders transmission from the medical command team to all other on- and off-site partners. It relieved the need of repeated back-and-forth communication with the 144, allowing both paramedic and doctor to focus on strategy and tactics rather than communication and logistics.

Assessing an intuitive condition for stability under a range of traffic conditions via a generalised Lu-Kumar network

We argue the importance both of developing simple sufficientconditions for the stability of general multiclass queueing networks and also of assessing such conditions under a range of assumptions on the weight of the traffic flowing between service stations. To achieve the former, we review a peak-rate stability condition and extend its range of application and for the latter, we introduce a generalisation of the Lu-Kumar network on which the stability condition may be tested for a range of traffic configurations. The peak-rate condition is close to exact when the between-station traffic is light, but degrades as this traffic increases.

Special investigation of the City of Grinnell Police Department for the period January 1, 2006 through April 30, 2008

Special investigation of the City of Grinnell Police Department for the period January 1, 2006 through April 30, 2008

Iowa Law Enforcement Academy Performance Report FY2012

The Iowa Law Enforcement Academy (ILEA) was created by an act of the Iowa legislature in 1967 with its purpose being to upgrade law enforcement to professional status. The specific goals were to maximize training opportunities for law enforcement officers, to coordinate training and to set standards for the law enforcement services.

Iowa Law Enforcement Academy FY2008 Annual Report and Performance Report

Annual Report Created by Academy Director E.A. (Penny) Westfall

First nationwide study on driving under the influence of drugs in Switzerland.

In Switzerland, a two-tier system based on impairment by any psychoactive substances which affect the capacity to drive safely and zero tolerance for certain illicit drugs came into force on 1 January 2005. According to the new legislation, the offender is sanctioned if Delta(9)-tetrahydrocannabinol THC is >or=1.5ng/ml or amphetamine, methamphetamine, 3,4-methylenedioxymethamphetamine (MDMA), 3,4-methylenedioxyethylamphetamine (MDEA), cocaine, free morphine are >or=15ng/ml in whole blood (confidence interval+/-30%). For all other psychoactive substances, impairment must be proven in applying the so-called "three pillars expertise". At the same time the legal blood alcohol concentration (BAC) limit for driving was lowered from 0.80 to 0.50g/kg. The purpose of this study was to analyze the prevalence of drugs in the first year after the introduction of the revision of the Swiss Traffic Law in the population of drivers suspected of driving under the influence of drugs (DUID). A database was developed to collect the data from all DUID cases submitted by the police or the Justice to the eight Swiss authorized laboratories between January and December 2005. Data collected were anonymous and included the age, gender, date and time of the event, the type of vehicle, the circumstances, the sampling time and the results of all the performed toxicological analyses. The focus was explicitly on DUID; cases of drivers who were suspected to be under the influence of ethanol only were not considered. The final study population included 4794 DUID offenders (4243 males, 543 females). The mean age of all drivers was 31+/-12 years (range 14-92 years). One or more psychoactive drugs were detected in 89% of all analyzed blood samples. In 11% (N=530) of the samples, neither alcohol nor drugs were present. The most frequently encountered drugs in whole blood were cannabinoids (48% of total number of cases), ethanol (35%), cocaine (25%), opiates (10%), amphetamines (7%), benzodiazepines (6%) and methadone (5%). Other medicinal drugs such as antidepressants and benzodiazepine-like were detected less frequently. Poly-drug use was prevalent but it may be underestimated because the laboratories do not always analyze all drugs in a blood sample. This first Swiss study points out that DUID is a serious problem on the roads in Switzerland. Further investigations will show if this situation has changed in the following years.