Waste identification diagrams

Value Stream Mapping (VSM) is a very popular tool in lean environments to represent production flows, mapping value stream of a product or family of products, and helps to identify some types of waste. Although very popular, this tool has some limitations as already described in many publications, especially in terms of restrictions in showing most types of waste as well as in its inability to represent various production routes. The purpose of this study is to introduce the waste identification diagram (WID), a new tool to represent production units with its different forms of waste, which overcomes some VSM limitations. The originality of WID comes from the use of its symbols’ dimensions to convey, in a visual and immediate way, relevant information about a production unit. In this paper, WID is applied on a production unit of a lift manufacturer, for testing its performance and comparing it to VSM. The main findings are that WID is in general more effective than VSM in terms of representation of complex production units and in terms of identification of more forms of waste. WID must however overcome some of its limitations such as the lack of information-flow representation and the links to suppliers and clients.     

Evaluation of the green supply chain management practices: a fuzzy ANP approach

Environmentally responsible manufacturing, green supply chain management (GSCM), and related principles have become important strategies for companies to achieve profit and gain market share by lowering their environmental impacts and increasing their efficiency. As environment has become a key strategic consideration in supply chains, this study examines the components and elements of GSCM and suggests a novel GSCM evaluation framework. It also provides a real-case study of Ford Otosan, one of the pioneering companies about environmental subjects in Turkey, to illustrate the industrial application of our theoretical assessment model. The identified components are integrated into a strategic assessment and evaluation tool using analytical network process (ANP). The dynamic characteristics and complexity of the GSCM analysis environment make the ANP technique a suitable tool for this study. Moreover, to cope with ambiguity and vagueness of the decision maker's evaluations, the fuzzy extension of the ANP method is preferred.     

On the simple linear regression model with correlated measurement errors

The simple linear regression model with measurement error has been subject to much research. In this work we will focus on this model when the error in the explanatory variable is correlated with the error in the regression equation. Specifically, we are interested in the comparison between the ordinary errors-in-variables estimator of the regression coefficient β$\beta$ and the estimator that takes account of the correlation between the errors. Based on large sample approximations, we compare the estimators and find that the estimator that takes account of the correlation should be preferred in most situations. We also compare the estimators in small sample situations. This is done by stochastic simulation. The results show that the estimators behave quite similarly in most of the simulated situations, but that the ordinary errors-in-variables estimator performs considerably worse than the estimator that takes account of the correlation for certain parameter combinations. In addition, we look briefly into the bias introduced by ignoring correlated errors when computing sample correlations, and in predictions.     

Internet Technology in Service of Personal Health Care Management: Patient Perspective

Internet technology has become an informational resource for most health care consumers. Online information, discussion, and support groups, in the form of message boards, listservs, and chat rooms are emerging as parts of virtual self-health-care network. This paper examines the extent to which participation in online health discussion groups was reported to be helpful in increasing medical knowledge and in enhancing the participatory patient role of health care consumers in interaction with health care service professionals. Data for this study was collected from 350 patients who participated in Internet discussion groups for cancer patients. The findings of the study indicated the important impact of Internet health discussion groups on health care management practices as perceived by health care consumers, including empowerment through knowledge and proactive participation in cancer care management. This research contributes to understanding the patient perspective and assesses the perceived importance of Internet groups by health care consumers.     

A breakpoint detection in the mean model with heterogeneous variance on fixed time intervals

Statistics and Computing - This work is motivated by an application for the homogenization of global navigation satellite system (GNSS)-derived integrated water vapour series. Indeed, these series...     

Signed compound poisson integer-valued GARCH processes

Abstract

We propose signed compound Poisson integer-valued GARCH processes for the modeling of the difference of count time series data. We investigate the theoretical properties of these processes and we state their ergodicity and stationarity under mild conditions. We discuss the conditional maximum likelihood estimator when the series appearing in the difference are INGARCH with geometric distribution and explore its finite sample properties in a simulation study. Two real data examples illustrate this methodology.     

Identity and Disruptiveness in Boys: Longitudinal Perspectives

After more than 30 years of research on identity, the links between identity and disruptive behaviors are not clear. This study compared the identity formation of boys with stable disruptive behaviors from age 6 to age 15 (n = 16), with the identity formation of boys that were never disruptive during the same period (n = 25). All boys came from low socio-economic status families. At age 9 and 11, identity was assessed with the The Self-Perception Profile for Children (Harter, 1985). At age 15, identity was assessed with the Extended Objective Measure of Ego Identity Status (Adams, Bennion, & Huh, 1989) and two scales of the Offer Self-Image Questionnaire (Offer, Ostrov, & Howard, 1981). Differences between disruptive and non-disruptive boys were found only for behavior in childhood and identity in ideological domains at age 15. Explanations for the weakness of the link between identity and disruptiveness are discussed.