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Smog seriously affects the ecological environment and poses a threat to public health. Therefore, smog control has become a key task in China, which requires reliable prediction.

This paper establishes a novel time-lag GM(1,N) model based on interval grey number sequences. Firstly, calculating kernel and degree of greyness of the interval grey number sequence respectively. Then, establishing the time-lag GM(1,N) model of kernel and degree of greyness sequences respectively to obtain their values after determining the time-lag parameters of two models. Finally, the upper and lower bounds of interval grey number sequences are obtained by restoring the values of kernel and degree of greyness.

In order to verify the validity and practicability of the model, the monthly concentrations of PM2.5, SO2 and NO2 in Beijing during August 2017 to September 2018 are selected to establish the time-lag GM(1,3) model for kernel and degree of greyness sequences respectively. Compared with three existing models, the proposed model in this paper has better simulation accuracy. Therefore, the novel model is applied to forecast monthly PM2.5 concentration for October to December 2018 in Beijing and provides a reference basis for the government to formulate smog control policies.

The proposed model can simulate and forecast system characteristic data with the time-lag effect more accurately, which shows that the time-lag GM(1,N) model proposed in this paper is practical and effective.

Based on interval grey number sequences, the traditional GM(1,N) model neglects the time-lag effect of driving terms, hence this paper introduces the time-lag parameters into driving terms of the traditional GM(1,N) model and proposes a novel time-lag GM(1,N) model.

The purpose of this paper is to introduce the concept of time lag to grey system models, and propose the grey system models with time lags.

The models were applied to calculate the time lags between spring flow and precipitation (i.e. hydraulic response time) and simulate karst spring discharge in Liulin Springs Basin, China.

The results show that the time lags of Lishi, Zhongyang, and Fangshan are three, five, and eight, respectively. By considering the time lags, we set up the grey system GM(1,4) response model of Liulin Springs discharge to precipitation of Lishi, Zhongyang, and Fangshan.

The results are in agreement with regional geological structure and provide a better understanding of karst hydrological processes of Liulin Springs Basin.

This paper reports research on the impact of mass communication and the passage of time on consumer satisfaction and loyalty in a high‐involvement service setting. The study was based on a survey of two groups of individuals. A short‐time lag group consisted of individuals who were surveyed immediately after receiving a service and one year later. A long‐time lag group consisted of individuals who were surveyed immediately after they received a service and two years later. Satisfaction and loyalty decreased from the initial time of the service encounter for both the short‐time and long‐time groups. While satisfaction and loyalty declined over time for both groups, the results revealed no difference in the change in satisfaction between the two groups. In addition, exposure to mass communication did not influence the change in satisfaction and intention to return over time.

In this chapter, the authors consider the role of time for research in occupational stress and well-being. First, temporal issues in studying occupational health longitudinally, focusing in particular on the role of time lags and their implications for observed results (e.g., effect detectability), analyses (e.g., handling unequal durations between measurement occasions), and interpretation (e.g., result generalizability, theoretical revision) were discussed. Then, time-based assumptions when modeling lagged effects in occupational health research, providing a focused review of how research has handled (or ignored) these assumptions in the past, and the relative benefits and drawbacks of these approaches were discussed. Finally, recommendations for readers, an accessible tutorial (including example data and code), and discussion of a new structural equation modeling technique, continuous time structural equation modeling, that can “handle” time in longitudinal studies of occupational health were provided.

Researchers in supply chain (SC) payment management have long sought to understand how project contractors, project owners, specialist contractors, and suppliers behave in the context of negotiating payment terms that improve contractors' SC cash flow.

Using a single case study approach, semi‐structured interviews with contract and project managers identify behavioral patterns. An analysis of categorical experiments and Spearman's correlation tests on 118 surveys from Taiwanese project contracting corporations generalizes the case findings.

The findings suggest that payment terms of project owners, specialists, and suppliers have an important impact on contractors' working capital. The findings also reveal that contractors pass project owners' payment terms down to specialists and suppliers, suggesting that contractors' behavior depends on that of the project owners.

This paper generalizes the case findings via surveys, but does not assume that the reported behavior patterns apply to all business enterprises. Future research could triangulate the findings.

This study combines qualitative and quantitative methods to understand how the project owner‐contractor‐supplier (or owner‐contractor‐specialist) triad behaves. Particularly, it focuses on an economic sector – real estate and construction – that receives less research interest than processing or manufacturing.

In this paper, an analysis is presented of the research funding towards nanotechnology at the National Nanotechnology Initiative (NNI) and its relationship to the research output in Nanoscope, an application area of nanotechnology.

The paper analyzes the data collected from 1997 till 2006 and derives a definitive time lag between the allocation of research funds and issued patents and published journals. This assessment is achieved by identifying growth trends in patents, funds and publications and doing a curve‐fit analysis using the Fisher‐Pry model. Linear regression analysis is used to show the correlation between the funding and research outputs. Alongside, non‐linear programming objective function optimization technique is used to derive the time lag in years for each of the research outputs from the year of funds granted.

This paper demonstrated that there is a strong correlation between research funding and different research outputs. The time lag between funding and patents issued is evident from the patent trend analysis and Bibliometric analysis. In the case of Nanoscope, the patent time lag was found to be approximately five to six years, for journal article it was approximately two to three years and conference presentations happened right after the funding. The research outputs showed similar trends and were found to be interdependent as evident from our mathematical analysis.

While this study has shown that lag times exist within the chosen example of Nanoscope, and furthermore can be calculated to a precise degree, further data points in terms of additional emerging technologies would support the hypothesis in a more general term. A future study can look at developing technology roadmaps of the future based on the funding happening today.

The work takes bibliometric analysis to a further intelligence and establishes key linkages between these indicators.

Computerising inventory control procedures is usually an attempt to gain better control over stock availability. The effectiveness of the procedures depends on the time delays imparted by such events as order processing and delivery. Through these time delays, much of a finished goods physical distribution system is linked together through the inventory control procedures. Changing the length of any one time element through changes in inventory stocking rules, order processing methods or selected transportation services impacts on the economics of the entire physical distribution system. Little is understood about the effects of time change in such complex systems. In this article, the actual computer inventory control procedures of a chemical company were computer simulated. Physical distribution system design decisions and their associated time delay effects were explored by interrogating the model. Surprising effects were discovered, some of them being counter‐intuitive to what simple theory would predict. Management guidelines were provided as to the system‐wide economic consequences of change in individual elements of a physical distribution system.

Construction cash flow models developed in previous researches demonstrated that cash flow profiles vary for differing procurement methods. However, the issue of whether contractors are satisfied or dissatisfied with payment terms impacting cash flows in differing procurement methods is yet to be investigated. This is the concern of this study. The study identified from literature, payment terms potentially thought to impact construction cash flow. Using a 6‐point Likert‐type scale, a questionnaire survey was administered to UK construction contractors in order to assess their level of satisfaction with identified payment terms influencing construction cash flow. Responses from the survey, which focused on traditional and design and build procurement methods were analysed using mean response analysis and one‐way analysis of variance. Results showed that while contractors were satisfied with most of the contractual factors investigated under both procurement systems, they were dissatisfied with two of the factors, namely, time lag between entitlement to receive and actually receiving cash payment and percentage of contract sum retained. This dissatisfaction calls for action to consider devising alternative means of dealing with retention and delay payments.

Today, a firm’s major concern is to know the way in which an innovation is adopted in the marketplace. The purpose of this paper is to focus on the two-stage nature of diffusion process in which the time lag between people being informed and their act of making final purchase is considered.

The paper discusses an approach based on the time lag for modeling awareness and adoption process as two separate and yet connected processes. Varying forms of time lag (constant, deterministic or random) have been considered while modeling the required framework. Furthermore, an equivalence approach has been shown between the present framework and the two well-known and established approaches of infinite queuing theory and hazard rate function.

The results are verified on sales data of two different consumer durables and it show good prediction capability of proposed models in capturing the real-life scenario. Further, the equivalence approach helps us to quantify such scenarios which were difficult to be modeled with any one particular approach. Further, the possibility of capturing different market scenarios by studying various distribution functions has been identified.

The proposed methodology is based on a two-stage adoption process. The same can be extended to a multi-stage adoption process as in today’s competitive environment. “Motivation” is one such factor that is highly important which can be considered in some later studies. In future, the authors wish to study the multi-stage adoption process considering the different forms of time lag function.

The equivalence approach discussed in the paper can help to cater the possibility of capturing different market scenarios by studying various distribution functions.

The proposed approach helps to cater the time lag between awareness and adoption process and develop different mean value functions to account for the manner in which sales are happening under different circumstances. The proposed methodical approach can also help decision makers in managing their available resources in a prudent manner.

The purpose of this paper is to assess cost of land title formalisation in Ghana from the standpoint of individual land/property owners with the view to suggesting a cost-effective means for title formalisation in the country.

The paper adopts a quantitative research approach with mainly questionnaire instruments to obtain data from real estate valuers, land agents and lawyers in Accra, Ghana's capital city.

Consistent with the literature, the paper found that title formalisation cost is high with extensive time lag. A substantial portion of the cost emanates from commuting cost for follow-ups to expedite action on title formalisation activities, cost of time lag and unofficial and professional fees for facilitation of title formalisation activities.

For land title formalisation to contribute to socio-economic development of Ghana and other developing countries, there is a need for effective and efficient land title formalisation regime to reduce excessive time lag and monetary cost for title formalisation.

Few studies have examined the extent of title formalisation cost in sub-Saharan Africa. Most of these studies tend to overlook several indirect costs and give misleading cost reportage or focus on social cost. The study analyses land title formalisation cost from individual land/property owners’ standpoint. The paper incorporates indirect costs and gives an idea as to the cost trend. Being first of its kind, the study presents a new dimension to the assessment of land title formalisation cost in Ghana for policy formulation and practice.