Uncertainty in measurement and control

Summary  Controlling is intervening in a situation on the basis of measurements. The three elements occurring in this definition may each contain an uncertainty that sets a limit to the control efficiency:
The measurements may be in error owing to both inaccuracies and sluggishness of the measurements. Proper and rapid data-processing is essential therefore.
The interventions may lose part of their effect through over-determinancy or dynamically unfavourable (sluggish) responses. In either case statistical calculations disclose the average control errors that are liable to be made, and also the way in which these can be minimized.
The situation may be unclear, i.e. the static and dynamic process characteristics are insufficiently known. In such cases regression and correlation techniques may aid in finding a solution.
Following a general review, we shall discuss in more detail those aspects that are bound up with the dynamics of the phenomena. Arguments from information theory reveal that the dynamic efficiency of control actions depends on correlation functions of time series (disturbances) and response curves of the systems (processes). The effects of disturbance correlation time, disturbance variance, sampling time, sample treatment, measuring errors, measuring time, rapidity of the intervention, etc., on the efficiency are elucidated by means of some formulae, graphs and examples.     

论电力稽查过程中“人性化”理念的内涵

电力稽查是用电管理一个不可或缺的内容。电力稽查的目的是提升电力使用率,防止电力无谓损耗及确保用电安全。在实施电力稽查的过程中,人性化管理方式的应用会大大提升电力稽查的效率,从而保障了电力稽查的实效性与持久性。在人性化管理中,处理好"以人为本"与"严格执法"的协调关系,就能保证电力稽查的实际效用。     

Omitted variables,variability of estimated parameters and the appearance of autocorrelated disturbances

This paper shows that in a standard regression model with omitted variables, the OLS formula for the estimated variance matrix of the regression coefficients is more likely to underestimate the appropriate criterion of estimator reliability which is the Mean Square Errors matrix. Using examples of two and three regressor models, we show that overestimation, though possible, occurs in rather special cases. Throughout, our analysis is contrasted with that of Chaudhuri (1977) and clarifies some ambiguities of that paper. Finally, we disagree with Chaudhuri who distinguishes between the corresponding coefficients in the correct and the misspecified models. This distinction is inappropriate and leads to a misplaced criticism of some GLS variants when errors are serially correlated. A first-order Markov process is an inexact representation of serial correlation which is due to omitted regressors.     

Examining the role of leadership,trust for school culture and policy

Quality of life relies on also the quality of working context and the group dynamic. Culture of schools, trust and leadership facilitate quality in fostering strategic policies in establishing policy and development. The aim of the research study is to examine the role of leadership, trust for school culture in regard to the perceptions of inspectors. As this research stands on qualitative nature, experiences, perceptions of research participants shape the current understanding to give insights on the role of leadership, trust. In addition, establishing school culture is a part of quality to set policy in terms of development, inspection is a moderation of encapsulating the nature of school culture. Interview was employed to gain understanding and experiences of inspectors in relation to leadership, trust for the school culture. Mission, vision of schools, principles of schools, loyalty to schools, policies, objectives of practices in schools, social interaction in schools. Thematic analysis through laddering was done that five themes were established in examining leadership, trust in the school culture. It is important that employees in the training organization act in a joint view on implementing educational objectives. This is achieved by developing positive attitudes in people and by being able to act constructively with each other. The research results revealed that the inspectors who are currently working at the Ministry of National Education have their views on the mission, vision and leadership of schools and what they think about school culture trust in schools.

     

Simultaneous inspection of several product characteristics

In this paper we consider 100% inspection of a product of which several characteristics have to satisfy given specification limits. A 100% inspection procedure may be necessary to bring the percentage of nonconforming items down to a level acceptable for the consumer. If one can observe the actual values of the characteristics, it would be possible to bring this percentage down to zero. However, quite often this is not possible, as a measurement error occurs in measuring the characteristics. Therefore, it is common practice to inspect each characteristic by comparing its measurement to a test limit which is slightly more strict than the corresponding specification limit. An item then is accepted if for each characteristic the measurement conforms to the corresponding test limit. However, instead of inspecting an individual characteristic merely using its own measurement, it is (much) more efficient to use the measurements of the other characteristics as well, especially if some of the characteristics are highly correlated. In this paper it is shown how the measurements of all the characteristics can be used to test whether an item is conforming.     

基于供应链管理的质量合作研究

传统的质量管理是针对一个组织而言,它必须有固定的组织机构进行质量职能分解。传统的质量管理组织结构形式为:总经理——职能部门领导——质量检查班组——质检员,各个层次的人员都负责自己的那部分质量管理。而在现代供应链管理模式下,不同的供应商生产模式、组织结构、生产能力及水平各不相同,生产周期亦是变动的,传统的质量管理方式显然不能适应,这时候,必须通过质量合作方式进行质量控制。本文对供应链管理模式下的质量合作进行了研究,以期指导企业在协作生产过程中的质量控制。     

论甘蔗制糖检验准确性提高的控制因素

在甘蔗制糖化学检验过程中,为了提高检验准确性,应严格控制检验流程的各个环节,从检验员的素质、样品的采集、仪器设备与计量器具的校准、试剂的配制、检验方法的选择、检验室的环境以及相关检验项目的检查等因素加以控制,确保获得准确的检验结果。     

Eenige statistische opmerkingen over verpakkingsen doseeringsproblemen

In packing powders, fluids and the like in mass production there are three frequency distributions of weights, viz. net weights, gross weights and tare weights. It is shown that by elementary statistical methods the standard deviation of one of these three distributions may be found by analysing the other two.
The excisting correlation, e.g. between net weights and tare weights, can be found by the same methods.     

Social support during COVID-19: Exploring the psychometric properties of the PSS-JSAS and its relationship with job search activities

The COVID-19 pandemic has highlighted the importance of social support for everyone. Supports from relatives, neighbors, and friends are more significant for a job seeker, especially during the pandemic. Accordingly, the present study explored the psychometric properties of the Perceived Social Support for Job Search Activities Scale (PSS-JSAS) in the Indian context with the help of two independent samples. First sample of 518 respondents was randomly divided into two subsamples using the random case selection feature in the statistical package for social sciences (SPSS). The exploratory factor analysis (EFA) was performed on the first subsample, which yielded a one-factor model explaining 47.23% of variations. The confirmatory factor analysis (CFA) conducted on the second subsample concluded a good model fit of PSS-JSAS. In the second sample, Cronbach's alpha and composite reliability values (greater than 0.70) established the scale's reliability. Results also revealed that the correlation coefficients between PSS-JSAS score, hope, self-efficacy, resilience, and optimism were 0.470, 0.552, 0.621, and 0.5 at p < 0.01. It also revealed a negative association with job search anxiety scores (r = −0.549, p < 0.01). Thus, PSS-JSAS was positively associated with PsyCap and negatively correlated with job search anxiety behaviors. It concluded the criterion validity of PSS-JSAS in the Indian context. Multigroup factor analysis concludes that the scale is equally valid for both Indian males and females. Hence, results reported adequate reliability and validity of the scale in the Indian context. These findings will encourage future researchers to investigate the phenomena of social support in the job search.     

Substituut-variabelen in correlatieberekingen

The recently repeated assertion that in correlation analysis it makes little difference whether one variable (x₂) is used instead of another one (x₃), provided the coefficient of correlation (r₂₃) between x₂ and x₃ is high, is scrutinized.
To that purpose the ranges of coefficients of correlation with respect to the substitute variable are expressed in formula 3. Moreover, by way of example, extreme values of coefficients of simple correlation (r₁₃ and r₃₄), of multiple correlation (R_1.34 and R_3.14) and of regression (α₁₃ and α₁₄, α₃₁ and α₃₄) relating to the substitute variable, are calculated on the basis of empirical values of coefficients of simple correlation relating to the substituted and the remaining variables.
The outcome of those calculations are summarized in the tables 1 and 3, and in the graph.
Table 1 presents ranges of r₁₃ for given values of r₁₂ and r₂₃, table 3 shows extreme values of coefficients of single and multiple correlation and regression in case an additional variable x₄ is introduced and r₁₂, r₁₄, r₂₄ and r₂₃ are given. The graph shows an ellipse as the boundary of the inner closed domain of compatible values of r₁₃ and r₃₄.
Those results clearly indicate the need for caution in substituting one variable by another.     

Scaling criterion of questionnaire items

Criterion scaling is a technique for scaling questionnaire item responses so as to maximize their correlation with an external criterion. The correlation between the criterion and the scaled item is equal to the correlation ratio or η coefficient. The results of rescaling the ninth grade questionnaire of the “Equal Educational Opportunity Survey” is presented and compared to the subjective scaling used in the Report. Criterion scaling increased all correlations but the change is not substantial enough to change the interpretation of the Report.     

Inconsistencies Across Three Contextual Meanings of Reliability

The purpose of this article is to assess the nature of reliability and its inconsistent definitions across three contextual (conceptual, measurement and statistical) levels under the traditional true score theory. Due to such inconsistencies, two existing quantitative approaches (using r and covariance) are not uniformly understood in Psychology and other disciplines; consequently, their applications to measurements and testings are limited to ambiguous interpretations at the conceptual and measurement levels. To examine the extent of this problem, a questionnaire including various contextual definitions and interpretations of reliability in the literature was distributed in a nationwide survey. Results from six groups of experts representing editors, professors and advanced graduate students in both quantitative and clinical areas indicate that all subject groups generally agreed that a reliable instrument possesses the characteristics of the repeatability of responses of all test-takers at the conceptual level, and the reproducibility of the instrument with little or no variations from the underlying true scores at the measurement level. However, between the editors and noneditors, the endorsements of the common definition at the measurement level show obvious discrepancies. Further, at the statistical level, significant differences were found not only between but also within subject-groups in their interpretations of product-moment correlations and Alpha coefficients for the assessment of reliability at the conceptual and measurement levels. The causes of such inconsistencies were discussed in terms of the inherent limitations of the two statistical approaches used and their insufficiencies for indexing the conceptual and measurement meanings of reliability. Finally, this paper called for developing new statistical indices that are coherent with conceptual and measurement definitions. Before such development, the capacities of existing reliability indices shall be redefined and their application qualifications shall be proportionally re-established for educational, research and clinical purposes.     

Interne leveringen in de inzet-afzetanalyse

Summary
By applying this relation all results in the two definition systems can be translated into each other. In this note we will analyze some relationships between increments in gross and net production.
It turns out that in case the external delivery structure changes {the non-diagonal coefficients of A), relative increments in gross and net production are identical.
A further result is that neither relative nor absolute increments in gross and net production are identical in case of changes in the internal delivery structure {the diagonal coefficients of A).
The third result is that relative increments in gross and net production are identical in case of a change in final demand.
Input-output analysis can be set up in gross or net terms. In the first case the internal deliveries of a sector are included in the table, in the other case they are neglected. These two different approaches give rise to two different leontief matrices: A and D.
Stone determined a relation between the two matrix multipliers (I-A)^-1 and (I-D)^-1     

Optimale betrouwbaarheid van parallelle meervoudige systemen

In this paper the reliability of parallel multi-component systems will be considered.
The number and kind of spare components wil be determined for maximum improvement in reliability under the assumption that limited funds are available for the purpose.     

A Statistical Approach to Assess Referendum Results: the Venezuelan Recall Referendum 2004

This article presents a statistical approach to assess the coherence of official results of referendum processes. The statistical analysis described is divided in four phases, according to the methodology used and the corresponding results: (1) Initial Study, (2) Quantification of irregular certificates of election, (3) Identification of irregular voting centers and (4) Estimation of recall referendum results.
The technique of cluster analysis is applied to address the issue of heterogeneity of the parishes with respect to their political preferences.
The Venezuelan recall referendum 2004 is the case study we used to apply the proposed methodology, based on the data published by the "Consejo Nacional Electoral" (CNE-National Electoral Council). Finally, we present the conclusions of the study which we summarize as follows: The percentage of irregular certificates of election is between 22.2% and 26.5% of the total; 18% of the voting centers show an irregular voting pattern in their certificates of election, the votes corresponding to this irregularity are around 2,550,000; The result estimate, using the unbiased votes as representative of the population for the percentage of YES votes against President Chávez is 56.4% as opposed to the official result of 41%.     

Produktiviteitsverhoging bij accountantscontrole door toepassing van gelaagde steekproeven

The auditor's productivity: application of stratified sampling to an auditing problem.
In this paper it is shown that the use of stratified sampling can lead to a considerable saving of costs in auditing operations and thus increases the auditor's productivity.
The sampling method to be described will render it possible to say that the total value of the transactions will not differ more than a fraction φ, given in advance, from the correct total value, apart from a probability not surpassing a preassigned level e, on condition that a certain acceptance criterion is fulfilled. Taking into account the auditing costs, the author gives an optimal sampling design and calculates the savings obtained.
Finally the theoretical results are applied to a population of clerical transactions, with an exponential and a logarithmico-normal distribution respectively.     

Survival and the art of profit maximization

We study the relationship between rationality and economic survival in a simple dynamic model, where agents from different populations interact repeatedly through random matching. An explicit criterion (“bankruptcy”) determines whether agents survive each interaction; all agents are presumed to be aware of this criterion. Survival in each interaction depends on two factors: the strategies agents adopt when they interact, and the wealth levels they bring to the game. The model is completely symmetric with the only difference between the agents of different populations being their objectives. We consider the case where there are two populations of agents in which all agents from one group have as their objective, maximizing the expected profits from each interaction, while all agents from the other attempt simply to maximize the probability of surviving (i.e., not going bankrupt in) the interaction. We show that under the equilibrium dynamics, the proportions of each group in the total population must be bounded away from zero, but the balance is in favor of the survival-probability maximizers in that their numbers as a fraction of total population must always exceed 1/2, and can be arbitrarily close to unity. On the other hand, the fraction of total wealth controlled by the expected profit maximizers must also be at least 1/2, and can asymptotically tend to unity.