Impact of Model Specification Decisions on Unit Root Tests

Performance of unit tests depends on several specification decisions prior to their application e.g., whether or not to include a deterministic trend. Since there is no standard procedure for making such decisions, therefore the practitioners routinely make several arbitrary specification decisions. In Monte Carlo studies, the design of DGP supports these decisions, but for real data, such specification decisions are often unjustifiable and sometimes incompatible with data. We argue that the problems posed by choice of initial specification are quite complex and the existing voluminous literature on this issue treats only certain superficial aspects of this choice. We also show how these initial specifications affect the performance of unit root tests and argue that Monte Carlo studies should include these preliminary decisions to arrive at a better yardstick for evaluating such tests.model specification, trend stationary, difference stationary

Most Stringent Test for Location Parameter of a Random Number from Cauchy Density

We study the test for location parameter of a random number from Cauchy density, focusing on point optimal tests. We develop analytical technique to compute critical values and power curve of a point optimal test. We study the power properties of various point optimal tests. The problem turned out to be different in its nature, in that, the critical value of a test determines the power properties of test. We found that if for given size  and any point m in alternative space, if the critical value of a point optimal test is 1, the test optimal for that point is the most stringent test.Cauchy density, Power Envelop, Location Parameter, Stringent Test

Zero-waste: a new sustainability paradigm for addressing global waste problem

There is a growing interest in addressing global waste problems by applying innovative ideas and philosophies such as zero-waste and circular economy. As a new sustainability paradigm, zero-waste challenges the common assumption of waste as a valueless and unavoidable by-product created at the end of the product’s life phase. Instead, it acknowledges that waste is a “misallocated resource” or “resource in transition”; produced during the intermediate phases of production and consumption activities. Waste should be recirculated to production and consumption processes. Therefore, zero waste means no “waste” would be wasted under the circular economy system. This chapter presents various examples of zero-waste practices derived from family, community, business, and city levels. In addition, zero-waste implementation strategies and actions are also discussed in the chapter. Despite its potential, the visionary zero-waste goals cannot be achieved without responsible global stewardship and active citizens’ role

Plastics: are they part of the zero-waste agenda or the toxic-waste agenda?

Background: Plastics were considered as a magical material owing to their strong, non-degradable and versatile characteristics. After five decades of mass application, plastics’ property of non-biodegradability has become one of the key concerns for scientists, civil society and government owing to the pollution and damage that plastics cause to our environment. Globally we have generated 8.3bn tonnes of plastics since 1950s and around 9% has been recycled, 12% incinerated and the remaining 79% of the plastics has ended up in the environment. The core question is, should this waste be minimised through the zero-waste agenda or banned through the toxic-waste agenda? Results: The study analyses the zero plastic waste agenda and the toxic plastic waste agenda. It analyses zero-waste practices at different levels including family to community, industry and city levels. In addition, the study investigates the need to phase out toxic plastics. The study identified the need for both approaches. As plastics promote the throwaway living which is responsible for generating undesirable waste, it should be tackled through better design principles and sustainable consumption practices for the short-term agenda. The study proposes a strategic zero plastic waste framework for moving towards a zero plastic waste society. At the same time, there is a need to identify those plastics that are leading to serious and toxic impacts through micro-particles that necessitate them to be phased out more quickly through transitioning to bio-plastics. Conclusions: Both zero plastic and zero toxic agendas are urgently needed. The study concludes that at least three things in the short term need to be implemented simultaneously to achieve a zero plastic waste society. Firstly, through zero-waste design - to eliminate creating any unnecessary plastic waste through closed-loop design thinking. Secondly, through responsible and collaborative consumption - to avoid and reduce generating avoidable plastic waste. Finally, through zero-waste management - to prioritise the value, retain the wasted materials and recover all resources. The study also establishes that a new long-term agenda needs to be created to identify those plastics that must be phased out owing to their toxicity. Consequently, the study suggests a process to achieve it in line with the transition to the post fossil-fuel era through United Nations initiatives as a joint action of the Paris Agreement and the Basel Convention

Integrated demand forecasting to support urban planning of low-carbon precincts: The waste scenario

Waste is a symbol of inefficiency in modern society and represents misallocated resources. This paper outlines an ongoing interdisciplinary research project entitled 'Integrated ETWW demand forecasting and scenario planning for low-carbon precincts' and reports on first findings and a literature review. This large multi-stakeholder research project has been designed to develop a shared platform for integrated ETWW (energy, transport, waste, and water) planning in a low-carbon urban future, focusing on synergies and alternative approaches to urban planning. The aim of the project is to develop a holistic integrated software tool for demand forecasting and scenario evaluation for residential precincts covering the four domains (ETWW), using identified commonalities in data requirements and model formulation. The authors of this paper are overseeing the waste domain, while other researchers in the team have expertise in the remaining domains. A major component of the project will be developing a method for including the impacts of household behaviour change in demand forecasting. In this way the overall carbon impacts of urban developments or redevelopments of existing precincts can be assessed effectively and efficiently. The resulting tool will allow urban planners, municipalities, and developers to assess the future total demands for energy, transport, waste, and water while in the planning phase. The tool will also help to assess waste management performance and materials flow in relation to energy and water consumption and travel behaviour, supporting the design and management of urban systems in different city contexts

Enabling an effective knowledge and information flow between the phases of building construction and facilities management

Purpose The purpose of this study is to investigate ways of transferring knowledge and information during the life-cycle phases of construction projects, particularly between the construction and occupancy phases, and to find an approach to minimise knowledge and information gaps during the handover process. Design/methodology/approach The study applied a qualitative approach involving a literature review and an archival analysis of information flow in the studied cases of a construction project, followed by a cross-cases analysis and expert interviews. Data on information flow were collected from three cases of building construction projects in Perth, Western Australia. In addition, a total of 18 local facilities management experts were interviewed to identify the key reasons of knowledge and information gaps and to propose an effective knowledge flow model. Findings The findings of this study indicated a significant knowledge and information gap, which exists during the handover process in construction projects in Western Australia. The findings of case analysis and expert interviews identified that the project handover guidelines were often ignored in construction projects in Western Australia, and the handover phase was not given the same priority as the design and construction phases by most of the project stakeholders, which led to information and knowledge gaps between the project construction and post-occupancy phases. The study conducted, integrated knowledge and information flow modelling to analyse the knowledge and information gaps followed by mapping the gaps against existing knowledge sharing frameworks (KSFs) before proposing an integrated knowledge sharing conceptual model to improve current practice and to enhance the information flow during the various phases of the construction project life cycle. Research limitations/implications The study is based on three cases in Perth, Western Australia, and thus the findings and recommendations are contextual. Whilst laying a good foundation to do so, further research is needed to investigate more cases in Western Australia and beyond to fully generalise the findings from this study. Originality/value The study contributes to improve the handover process and information flows in project life-cycle phases in Western Australia and develop an information flow model followed by bringing together existing KSFs, namely, the open communication channel (OCC), soft landing framework (SLF) and building information modelling (BIM), to propose an integrated knowledge sharing conceptual model. The methodology used here to analyse the information flow in a diagrammatic manner, the mapping of FM issues against the KSFs’ capabilities and a conceptual model to facilitate change in the industry’s silo mindset are the main contributions of this paper

Resource harvesting through a systematic deconstruction of the residential house: A case study of the 'Whole House Reuse' project in Christchurch, New Zealand

© 2018 by the authors. This study analyzes the case study of a deconstruction project called the 'Whole House Reuse' (WHR) which aimed, firstly, to harvest materials from a residential house, secondly, to produce new products using the recovered materials, and thirdly, to organize exhibition for the local public to promote awareness on resource conservation and sustainable deconstruction practices. The study applies characterization of recovered materials through deconstruction. In addition to the material recovery, the study assesses the embodied energy saving and greenhouse gas emissions abatement of the deconstruction project. Around twelve tons of various construction materials were harvested through a systematic deconstruction approach, most of which would otherwise be disposed to landfill in the traditional demolition approach. The study estimates that the recovered materials could potentially save around 502,158 MJ of embodied energy and prevent carbon emissions of around 27,029 kg (CO2e). The deconstruction could eventually contribute to New Zealand's national emission reduction targets. In addition, the project successfully engages local communities and designers to produce 400 new products using the recovered materials and exhibits them to the local people. The study concludes that there is a huge prospect in regard to resource recovery, emission reduction, employment, and small business opportunities using deconstruction of the old house. The sociocultural importance of the WHR project is definitely immense; however, the greater benefits of such projects are often ignored and remain unreported to wider audiences as most of the external and environmental costs are not considered in the traditional linear economy. It is acknowledged that under a favorable market condition and with appropriate support from local communities and authorities, deconstruction could contribute significantly to resource conservation and environmental protection despite its requirement of labor-intensive efforts

Supporting urban planning of low-carbon precincts: Integrated demand forecasting

Waste is a symbol of inefficiency in modern society and represents misallocated resources. This paper outlines an on-going interdisciplinary research project entitled "Integrated ETWW demand forecasting and scenario planning for low-carbon precincts" and reports on first findings and a literature review. This large multi-stakeholder research project develops a shared platform for integrated ETWW (energy, transport, waste and water) planning in a low-carbon urban future, focusing on synergies and alternative approaches to urban planning. The aim of the project is to develop a holistic integrated software tool for demand forecasting and scenario evaluation for residential precincts, covering the four domains, ETWW, using identified commonalities in data requirements and model formulation. The authors of this paper are overseeing the waste domain. A major component of the project will be developing a method for including the impacts of household behavior change in demand forecasting, as well as assessing the overall carbon impacts of urban developments or redevelopments of existing precincts. The resulting tool will allow urban planners, municipalities and developers to assess the future total demands for energy, transport, waste and water whilst in the planning phase. The tool will also help to assess waste management performance and materials flow in relation to energy and water consumption and travel behavior, supporting the design and management of urban systems in different city contexts. © 2013 by the authors

Model specification, observational equivalence and performance of unit root tests

In this paper we highlight the necessity of new criteria for evaluation of performance of unit root tests. We suggest focusing directly on the reasons that create ambiguity in unit root test’s results. Two reasons for unsatisfactory properties of unit root tests can be found in the literature (i) the model misspecification and (ii) observational equivalence. Regarding first reason, there is immense literature on several components of model specification covering specification techniques, consequence of misspecification and robust methods. However complete model specification involves multiple decisions and most of studies on performance of unit root tests do not address issue of multiple specification decisions simultaneously. The Monte Carlo studies are conditional on some of implicit specification and for Monte Carlo; these specifications are by construction valid. But for real data, the implicit decisions are often not true and specification decisions need to be endogenized. A closer match with real case is possible if multiple specification decisions are endogenized, thus providing more reliable measure of performance of unit root tests. Second problem in differentiating trend and difference stationary process is the observational equivalence between two processes. We suggest exploring data generating processes with different long run dynamics and small sample equivalence so that a researcher should have an idea about other plausible models for a data set for which he has estimated some model

Impact of Model Specification Decisions on Unit Root Tests

Performance of unit tests depends on several specification decisions prior to their application e.g., whether or not to include a deterministic trend. Since there is no standard procedure for making such decisions, therefore the practitioners routinely make several arbitrary specification decisions. In Monte Carlo studies, the design of DGP supports these decisions, but for real data, such specification decisions are often unjustifiable and sometimes incompatible with data. We argue that the problems posed by choice of initial specification are quite complex and the existing voluminous literature on this issue treats only certain superficial aspects of this choice. We also show how these initial specifications affect the performance of unit root tests and argue that Monte Carlo studies should include these preliminary decisions to arrive at a better yardstick for evaluating such tests