Time‐change models for asymmetric processes

Many records in environmental sciences exhibit asymmetric trajectories. The physical mechanisms behind these records may lead for example to sample paths with different characteristics at high and low levels (up–down asymmetries) or in the ascending and descending phases leading to time irreversibility (front–back asymmetries). Such features are important for many applications, and there is a need for simple and tractable models that can reproduce them. In this paper, we explore original time‐change models where the clock is a stochastic process that depends on the observed trajectory. The ergodicity of the proposed model is established under general conditions, and this result is used to develop nonparametric estimation procedures based on the joint distribution of the process and its derivative. The methodology is illustrated on meteorological and oceanographic data sets. We show that, combined with a marginal transformation, the proposed methodology is able to reproduce important characteristics of the data set such as marginal distributions, up‐crossing intensity, and up–down and front–back asymmetries.     

Subsequent Migration of Immigrants Within Australia, 1981–2016

Australia is a major immigration country and immigrants currently represent around 28% of the total population. The aim of this research is to understand the long-term consequences of this immigration and, particularly, how migrants respond to opportunities within the country after arriving through the process of subsequent (internal) migration. The focus is on major immigrant groups in Australia, including persons born in the United Kingdom, New Zealand, China and India, and how their patterns differ from persons born in Australia. To conduct this analysis, we have gathered data for a 35-year period based on quinquennial census data. We also obtained birthplace-specific mortality data for constructing multiregional life tables for the immigrant populations. Subsequent migration is important for understanding population redistribution, and the relative attractiveness of destinations within host countries. Our results highlight the importance of subsequent migration and the diversity of migration behaviours amongst different immigrant groups in the context of overall declines in internal migration since 1981.     

A SIMULATION ANALYSIS OF THE JAPANESE JUST-IN-TIME TECHNIQUE (WITH KANBANS) FOR A MULTILINE,MULTISTAGE PRODUCTION SYSTEM

The Japanese “just-in-time with kanban” technique reduces in-process inventory to absolute minimal levels, in concert with the Japanese belief that inventory is an unnecessary evil. Due to the success of Japanese firms that employ this type of system, American firms would like to import this technique and emulate Japanese successes. But this Japanese success may be attributable not only to the just-in-time with kanban technique but also to the production environment in which the technique is employed. This paper simulates the just-in-time with kanban technique for a multiline, multistage production system in order to determine its adaptability to an American production environment that might include such characteristics as variable processing times, variable master production scheduling, and imbalances between production stages. The results have practical implications for those firms considering adoption of the Japanese technique.     

On edge orienting methods for graph coloring

We consider the problem of orienting the edges of a graph so that the length of a longest path in the resulting digraph is minimum. As shown by Gallai, Roy and Vitaver, this edge orienting problem is equivalent to finding the chromatic number of a graph. We study various properties of edge orienting methods in the context of local search for graph coloring. We then exploit these properties to derive four tabu search algorithms, each based on a different neighborhood. We compare these algorithms numerically to determine which are the most promising and to give potential research directions.     

Immigrant incorporation in the garment industry of Los Angeles

This study expands immigrant social network theory and examined employment patterns in the garment industry in Los Angeles, California, among Latino workers employed by Asian immigrant entrepreneurs. The study determined that a large percentage of immigrant employees found their jobs through the immigrant economy. Entrepreneurship increased the supply of local jobs and expanded the economy at destination at no expense to natives. Immigrant entrepreneurs bought firms from nonimmigrant owners or started new ones with an immigrant labor supply. Massey's index is flawed due to its exclusion of the role of entrepreneurs. Migration networks facilitate entrepreneurship, but some ethnic groups have fewer entrepreneurs, such as Mexicans and Central Americans. A 1993 Los Angeles survey identified 3642 garment factories in its county. Mean employment was 27.1 persons. The garment industry was the 4th largest industry in the area in 1996, with 98,700 employees. It represented 6% of all wage and salary employees in the City and 5.5% of the immigrant labor force in the County in 1990. 93% of garment workers in 1990 were immigrants. It is estimated that 51% of garment factory owners were Asians; most employees were Latinos. Census figures on sewing machine operators indicated 47.3% of owners were Whites and 42.45 were Asians. 53.3% of employees were other ethnic groups, 14.5% were Asians, and 32.2% were Whites. It is estimated that 47.2% of total employment was due to the immigration economy. 71.5% of the total employment in the garment industry was in the immigrant sector.     

Lattices of choice functions and consensus problems

In this paper we consider the three classes of choice functions satisfying the three significant axioms called heredity (H), concordance (C) and outcast (O). We show that the set of choice functions satisfying any one of these axioms is a lattice, and we study the properties of these lattices. The lattice of choice functions satisfying (H) is distributive, whereas the lattice of choice functions verifying (C) is atomistic and lower bounded, and so has many properties. On the contrary, the lattice of choice functions satisfying (O) is not even ranked. Then using results of the axiomatic and metric latticial theories of consensus as well as the properties of our three lattices of choice functions, we get results to aggregate profiles of such choice functions into one (or several) collective choice function(s).The authors thank two anonymous referee for several useful remarks or corrections on the first version of the paper.     

Family Therapy with the Learning Disabled Child and His/Her Family

No therapist can come in contact with and treat children with minimal brain damage or specific learning disabilities without being struck by the fact that there are numerous intertwined factors that have contributed to and continue to perpetuate the problems. In addition to the helping approaches which have been utilized in recent years, such as tutoring, special education, and child therapy, this article elaborates the importance of utilizing family therapy as the treatment of choice sometime during the course of treating the child and helping the parents to understand and deal with their handicapped youngster.     

Robustness evaluation of multisite distributed schedule with perturbed virtual jobshops

A method for evaluating the robustness of medium term multisite distributed schedule is presented. The method of robustness evaluation is based on steps and tools associated with the conceptual model of a MultiSite Reactive Production Activity Control (MSR-PAC). The MSR-PAC makes it possible to study the sensitivity of the scheduled plans in presence of perturbations. These must be evaluated before being dispatched to the shop-floors. At present, to the best of the authors' knowledge, there is no means to make this evaluation in the distributed systems such as extended enterprise. The monitoring of errors is based on the discrepancy between the two flow-shape functions that model respectively the dynamics of the scheduled manufacturing orders and the state of the perturbed production. The MSR-PAC is based on a multisite agent system and on the monitoring of the perturbed virtual jobshops. The method can also be used for controlling short term distributed production activities.