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Keywords = software release policy

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31 pages, 4521 KiB  
Article
NHPP Software Reliability Model with Rayleigh Fault Detection Rate and Optimal Release Time for Operating Environment Uncertainty
by Kwang Yoon Song and In Hong Chang
Appl. Sci. 2024, 14(21), 10072; https://doi.org/10.3390/app142110072 - 4 Nov 2024
Viewed by 543
Abstract
Software is used in diverse settings and depends on development and testing environments. Software development should improve the reliability, quality, cost, and stability of software, making the software testing period crucial. We proposed a software reliability model (SRM) that considers the uncertainty of [...] Read more.
Software is used in diverse settings and depends on development and testing environments. Software development should improve the reliability, quality, cost, and stability of software, making the software testing period crucial. We proposed a software reliability model (SRM) that considers the uncertainty of software environments and the fault detection rate function as a Rayleigh distribution, with an explicit mean value function solution in the model. The goodness-of-fit of the proposed model relative to several existing nonhomogeneous Poisson process (NHPP) SRMs is presented based on three software application failure datasets. Further, a cost model is also presented that addresses the error-removal risk level and required time. The optimal testing release policy for minimizing the expected total cost (ETC) is also determined for NHPP SRMs. The impact of the software environment is studied by varying it, and the optimal release times and minimum ETCs are compared. The goodness-of-fit comparison confirmed that the proposed model has more accurate prediction values than other models. Further, whereas the existing models applied to the cost model do not change after a certain operation period, the proposed model yields changes in release time even for long operating periods. Full article
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<p>Classification of SRMs.</p>
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<p>Software cost model structure.</p>
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<p>MVFs of all eight models listed in <a href="#applsci-14-10072-t001" class="html-table">Table 1</a>.</p>
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<p>Relative errors of eight models in <a href="#applsci-14-10072-t001" class="html-table">Table 1</a>.</p>
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<p>95% confidence interval of the proposed model.</p>
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<p>ORTime variation with minimum ETC for each model in Case #1 on Dataset #1.</p>
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<p>ORTime variation with minimum ETC for the proposed model in Case #1 on real data.</p>
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<p>ORTime versus function of the minimum ETC for the proposed model in Cases #2–#5 on real data.</p>
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<p>ORTime variation with minimum ETC for each model in Case #2.</p>
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<p>ORTime variation with minimum ETC for each model in Case #3.</p>
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<p>ORTime variation with minimum ETC for each model in Case #4.</p>
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<p>ORTime variation with minimum ETC for each model in Case #5.</p>
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18 pages, 1917 KiB  
Article
Policy Instrument Preferences and Optimization Strategies: Based Text Analysis of Provincial-Level Education Digitalization Policy from China
by Jing Cao, Chunmei Yu and Yan Wu
Educ. Sci. 2024, 14(5), 539; https://doi.org/10.3390/educsci14050539 - 16 May 2024
Viewed by 954
Abstract
In the context of world education digitalization, the Chinese government has formulated China’s education digitalization strategy. The education digitalization policy tools of provincial governments are an important factor affecting the effectiveness of education digitalization policies. In this study, a text quantification and content [...] Read more.
In the context of world education digitalization, the Chinese government has formulated China’s education digitalization strategy. The education digitalization policy tools of provincial governments are an important factor affecting the effectiveness of education digitalization policies. In this study, a text quantification and content analysis is conducted on educational digital policy documents released by eight provinces of China during the 14th Five-Year Plan period in China. This is based on a two-dimensional analysis framework of “instruments-value” using instrument types and policy principles, and NVivo software. The research outcomes reveal the following: (1) The distribution of educational digital policy instrument types is uneven, with an excess of supply-side instruments and a noticeable shortage of demand-side instruments. (2) Different policy instruments exhibit varying degrees of preference in implementing policy principles. There is a stronger emphasis on technology application and balanced development, while the emphasis on service principles promoting diverse participation is relatively weaker. (3) The policy instruments that facilitate interaction between policymakers and educational entities require further strengthening. In light of these findings, local governments in China should strengthen the use of demand-side policy instruments to achieve comprehensiveness and sustainability in educational digitalization. Policymakers should pay more attention to the demands of educational entities to shift educational digitalization from being technology driven to being demand driven. Furthermore, policy instrument selection should adhere to the value of serving and supporting individuals and reinforce the concept of multi-participation in their development, ultimately improving the precision and coordination of policies, and achieving a harmonious integration of technological and value aspects of policy instruments. Full article
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<p>Mechanism of policy instruments on the digital transformation of education.</p>
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<p>Two-dimensional analytical framework.</p>
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<p>Distribution of policy instruments for digitalization of education.</p>
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<p>The ratio of supply-side policy instruments to demand-side policy instruments in different provinces.</p>
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<p>Distribution of supply-oriented policy instrument codes.</p>
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<p>Distribution of demand-oriented policy instrument codes.</p>
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<p>Distribution of environment-oriented policy instrument codes.</p>
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<p>Distribution of policy principal codes.</p>
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10 pages, 488 KiB  
Article
Influences of Software Changes on Oxycodone Prescribing at an Australian Tertiary Emergency Department: A Retrospective Review
by Giles Barrington, Katherine Davis, Zach Aandahl, Brodie-Anne Hose, Mitchell Arthur and Viet Tran
Pharmacy 2024, 12(2), 44; https://doi.org/10.3390/pharmacy12020044 - 1 Mar 2024
Viewed by 1994
Abstract
Opioid prescribing and dispensing from emergency departments is a noteworthy issue given widespread opioid misuse and diversion in many countries, contributing both physical and economic harm to the population. High patient numbers and the stochastic nature of acute emergency presentations to emergency departments [...] Read more.
Opioid prescribing and dispensing from emergency departments is a noteworthy issue given widespread opioid misuse and diversion in many countries, contributing both physical and economic harm to the population. High patient numbers and the stochastic nature of acute emergency presentations to emergency departments (EDs) introduce challenges for prescribers who are considering opioid stewardship principles. This study investigated the effect of changes to electronic prescribing software on prescriptions with an auto-populated quantity of oxycodone immediate release (IR) from an Australian tertiary emergency department following the implementation of national recommendations for reduced pack sizes. A retrospective review of oxycodone IR prescriptions over two six-month periods between 2019 and 2021 was undertaken, either side of a software adjustment to reduce the default quantities of tablets prescribed from 20 to 10. Patient demographic details were collected, and prescriber years of practice calculated for inclusion in linear mixed effects regression modelling. A reduction in the median number of tablets prescribed per prescription following the software changes (13.5 to 10.0, p < 0.001) with little change in the underlying characteristics of the patient or prescriber populations was observed, as well as an 11.65% reduction in the total number of tablets prescribed. The prescriber’s years of practice, patient age and patient sex were found to influence increased prescription sizes. Reduced quantity of oxycodone tablets prescribed was achieved by alteration of prescribing software prefill parameters, providing further evidence to support systems-based policy interventions to influence health care providers behaviour and to act as a forcing function for prescribers to consider opioid stewardship principles. Full article
(This article belongs to the Special Issue Pharmacists’ Role in Reducing Problematic Opioid Use)
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<p>Frequency of oxycodone IR prescriptions and quantity for tablets per prescription following changes in electronic prescribing software in an Australian tertiary ED, prefilled values of oxycodone IR were reduced from 20 (2019) to 10 (2019).</p>
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34 pages, 1059 KiB  
Article
Energy-Based Economic Sustainability Protocols
by Federico Taranto, Luigi Assom and Alessandro Chiolerio
Appl. Sci. 2023, 13(11), 6554; https://doi.org/10.3390/app13116554 - 28 May 2023
Cited by 2 | Viewed by 1762
Abstract
In this paper, a sustainability framework for global and scalable payment systems is introduced. It is based on energy and resource consumption and pollutant classes and is inspired by ISO14040 principles. This paper aims to provide guidance for the implementation of blockchain-based technologies [...] Read more.
In this paper, a sustainability framework for global and scalable payment systems is introduced. It is based on energy and resource consumption and pollutant classes and is inspired by ISO14040 principles. This paper aims to provide guidance for the implementation of blockchain-based technologies in a Life-Cycle Assessment methodology. The impact criteria adopted in this first approximation are at the stakeholders’ level. Enhancement through Enterprise Resource Planning software integration is considered to extend the impact allocation to the level of products and services. The system is designed on environmental economic models based on resources. A continuous depletion in the quality of exchangeable output is also modelled with respect to raw material consumption. We also consider the geophysical coordinates of pollutant emissions and the concurrent emission of pollutants affecting the quality of such outputs. This framework aims to be initially applied to the CO2eq indicator, which is identified by a set of aerial pollutants with global warming potential as proposed by the Intergovernmental Panel on Climate Change. Nonetheless, an incentive scheme within the so-defined payment system is possible and herein suggested, including the extension to other impact criteria (e.g., pollutants released in water and soil). Multiple approximations are made in order to overcome the difficulty in sampling reservoirs of natural resources, such as (1) disregarding regeneration rate and physical limits of raw material reservoirs and (2) estimating the minimum amount of pollutants affecting the perceived quality of economic transactions. Eventually, sampling policies are outlined as fundamental tactics to foster the effectiveness of this framework. Full article
(This article belongs to the Section Green Sustainable Science and Technology)
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<p>System boundaries and energy and information flows.</p>
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<p>Protocol gate-to-gate diagram.</p>
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<p>Interaction of stakeholders in a simplified supply chain sub-system.</p>
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<p>Social optimum.</p>
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<p>Pigouvian taxation in a real case scenario.</p>
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<p>Social indicators (optimum in the alternative space—fixed vs. custom tax).</p>
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<p>Trajectories of the decisional problem—fixed vs. custom tax.</p>
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<p>Decisional scenario—fixed vs. custom tax.</p>
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<p>(<b>a</b>) Social indicators (fixed tax and custom tax) in the alternative space. (<b>b</b>) Decisional scenario.</p>
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28 pages, 8154 KiB  
Article
Creative Economy and Sustainable Development: Shaping Flexible Cultural Governance Model for Creativity
by Wen-Jie Yan and Shu-Tang Liu
Sustainability 2023, 15(5), 4353; https://doi.org/10.3390/su15054353 - 28 Feb 2023
Cited by 8 | Viewed by 2700
Abstract
With the development of cultural democratization, countries have attached increasing importance to the protection of cultural rights and the promotion of sustainable cultural development. The establishment of a flexible cultural governance model may release the transformative force of culture and creativity, gradually spread [...] Read more.
With the development of cultural democratization, countries have attached increasing importance to the protection of cultural rights and the promotion of sustainable cultural development. The establishment of a flexible cultural governance model may release the transformative force of culture and creativity, gradually spread cultural values and ideas into governance, and shift activities to more sustainable behavior. This research was divided into two stages. In the first stage, CiteSpace was used to conduct a co-citation analysis of documents published between 2013 and 2022 in the Web of Science database. The results were combined with existing cultural development and value indicators from many countries to design cultural impact indicators suitable for evaluating the sustainable development of creative industries. In the second stage, a questionnaire survey was conducted on the cultural industry, the creative economy, and cultural consumption. Through statistical analysis, six dimensions were obtained, and 20 indicators were cultural sustainability, cultural democracy, cultural innovation, cultural industrialization, cultural vitality, and cultural policy systematization. The cultural governance framework of the creative economy and sustainable development was established through AMOS software. This study found that the humanistic rationality of cultural governance has a significant improvement and stable role in promoting the governance of cultural policies. Adjustable cultural impact indicators are effective cultural practices for shaping and framing creative industries, which should be invented, stabilized and improved. Full article
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<p>Creative and cultural industry development model integrating policy guidance and resource activation.</p>
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<p>Domain-level citation patterns in CCI research (2013–2022, in Web of Science): The cluster on the left indicates the retrieved research frontier, while the cluster on the right indicates the location of their references; Citation tracks and reference tracks are distinguished by the color of the reference area; The thickness of these tracks is proportional to the reference frequency of the z-score.</p>
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<p>Research Process and Design.</p>
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<p>A landscape view of the co-citation network. (LRF = 3, LBY = 5, and e = 1.0; Timespan: 2013–2022; Slice Length = 1).</p>
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<p>A landscape view of the co-citation network: (<b>a</b>) Timespan: 2013; (<b>b</b>) Timespan: 2022; (<b>c</b>) Timespan: 2023.</p>
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<p>A landscape view of the co-citation network: (<b>a</b>) Timespan: 2013; (<b>b</b>) Timespan: 2022; (<b>c</b>) Timespan: 2023.</p>
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<p>A timeline visualisation of 20 clusters.</p>
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<p>City heat map.</p>
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<p>Research model.</p>
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<p>Cultural governance model of a creative economy.</p>
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<p>Flexible cultural governance model of creative economy: (<b>a</b>) self-management; (<b>b</b>) legality; (<b>c</b>) policy; (<b>d</b>) democracy.</p>
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<p>Path coefficient values of 20 indicators.</p>
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<p>Sustainable cultural and economic ecological system.</p>
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24 pages, 3468 KiB  
Article
Sustainable Management of Food Waste during COVID-19 Pandemic: Insights into Irrational Food Hoarding among Chinese Citizens
by Kangjie Zhang, Fuduo Li, Huanli Li and Changbin Yin
Foods 2022, 11(24), 4049; https://doi.org/10.3390/foods11244049 - 14 Dec 2022
Cited by 2 | Viewed by 1903
Abstract
During the COVID-19 pandemic, food waste caused by excessive hoarding has accounted a large proportion of the total food waste in urban Chinese households, which indicates that reducing food hoarding has become key to managing household food waste. This study therefore explored the [...] Read more.
During the COVID-19 pandemic, food waste caused by excessive hoarding has accounted a large proportion of the total food waste in urban Chinese households, which indicates that reducing food hoarding has become key to managing household food waste. This study therefore explored the behavioral mechanisms underlying excessive food hoarding among citizens. Based on a sample set of 511 respondents surveyed in Beijing, Hefei, and Guiyang in July 2022, a PLS-SEM model was conducted using SmartPLS 3.0 software to simulate the decision-making process of food hoarding. The following results were found. First, among the households with hoarding, 66.37% had some degree of food waste. Second, hoarding preference was the direct predictor of hoarding behavior, which means that hoarding behavior can be effectively controlled by regulating preferences. Third, group influence including homology consistency and social network support, as well as psychological panic, both enhanced citizens’ hoarding preference and induced hoarding behavior. Therefore, it is necessary to weaken group influence and try to help citizens overcome panic. Finally, food supply information release can not only alleviate citizens’ psychological panic and weaken group influence, but also block the transformation of preference into behavior. The above results are of great importance for the design of management policies for food waste caused by irrational hoarding during the pandemic. Full article
(This article belongs to the Section Food Security and Sustainability)
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<p>Food waste caused by IFHB.</p>
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<p>The research framework of this study.</p>
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<p>Citizens’ food hoarding behavior and food waste resulting from hoarding. Note: both episodic and persistent hoarding is considered to be food hoarding behavior.</p>
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<p>The structure of food hoarding and food waste.</p>
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<p>Descriptive statistics of respondents’ responses to survey items.</p>
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<p>Heterogeneity test of HPR and IFHB among cities.</p>
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<p>Model estimation results without consideration of the moderating effect of FSIR.</p>
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<p>Estimation results of the moderating effect of FSIR.</p>
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18 pages, 4093 KiB  
Article
Decision Making of Software Release Time at Different Confidence Intervals with Ohba’s Inflection S-Shape Model
by Ting-Cheng Chang, Ying Lin, Kunquan Shi and Teen-Hang Meen
Symmetry 2022, 14(3), 593; https://doi.org/10.3390/sym14030593 - 16 Mar 2022
Cited by 10 | Viewed by 2040
Abstract
Software developers need information for deciding the optimal time for software release with improved software reliability. However, it is not easy for them to decide when and how to release newly developed software to the market. For a decision, the reliability and test [...] Read more.
Software developers need information for deciding the optimal time for software release with improved software reliability. However, it is not easy for them to decide when and how to release newly developed software to the market. For a decision, the reliability and test costs of the software need to be balanced carefully for avoiding unnecessary confusion and users’ complaints. To address this need, related research has been carried out to propose an appropriate tool for such decisions. In many studies, software reliability growth models (SRGMs) were applied using the concept of confidence intervals to estimate the reliability of software. Confidence intervals were calculated on the basis of the assumption of a normal distribution showing the symmetrical occurrence of data with the mean as a center. However, the reliability data of software do not always have such symmetry for assuming the normal distribution. Therefore, it is necessary to propose a method for overcoming the mean value randomness that causes asymmetry in the related data. In previous studies, estimating variance and mean of errors of software was not considered, which led to the unreliable estimation of the confidence intervals of the mean value for decision making. Previous studies also lacked practicability in applications due to statistics from the asymmetrical data distribution. As a result, software developers could not effectively evaluate the possible risk related to the software release time. To improve the estimation, we employ the inflection S-shape model to propose the SRGM on the basis of confidence intervals assumed to come from the normal distribution. The proposed model allows determining the optimal time for software release with the consideration of its potential risk. For efficient determination, the architecture and user interface of the computation system are also proposed. Full article
(This article belongs to the Special Issue Selected Papers from IIKII 2021 Conferences)
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<p>Confidence interval of traditional methods with a normal distribution.</p>
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<p>Confidence interval of the proposed method with Student’s <span class="html-italic">t</span> distribution.</p>
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<p>Confidence interval at 95% and the fitting result for Goel and Okumoto models.</p>
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<p>Confidence interval (95%) and the fitting result for Yamada delayed S-shaped model.</p>
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<p>Confidence interval (95%) and the fitting result for Musa’s model.</p>
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<p>Confidence interval (95%) and the fitting result for Ohba’s inflection model (the proposed model).</p>
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<p>Computerized implementation architecture.</p>
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<p>Concept design of user interface for the decision support system.</p>
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<p>The testing time expected vs. testing cost of the testing project.</p>
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<p>The testing time vs. expected reliability of the testing project.</p>
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21 pages, 5505 KiB  
Article
Omni-Chanel Network Design towards Circular Economy under Inventory Share Policies
by Damla İzmirli, Banu Y. Ekren, Vikas Kumar and Siwarit Pongsakornrungsilp
Sustainability 2021, 13(5), 2875; https://doi.org/10.3390/su13052875 - 7 Mar 2021
Cited by 14 | Viewed by 4573
Abstract
In this paper, we study inventory share policies in an omni-channel supply network, to contribute to the circular economy (CE) concept. Lateral inventory share implementation provides flexibility and profitability in the supply chain by allowing inventory share between the same echelon locations in [...] Read more.
In this paper, we study inventory share policies in an omni-channel supply network, to contribute to the circular economy (CE) concept. Lateral inventory share implementation provides flexibility and profitability in the supply chain by allowing inventory share between the same echelon locations in a network. Total holding costs and transportation costs can be reduced by lateral inventory share applications, which also contribute to decreased material usage for production over time, as well as reduced CO2 emission released by transportation. Technological and Internet of Things (IoT) developments make it possible for companies to share their real-time information with each other for uninterrupted marketing experiences. With such a connected network, companies aim to increase their profitability and responsiveness to their customers. We explore a well-designed inventory share policy towards the CE concept under an (s, S) inventory control policy. We simulate several pre-defined share designs by Arena 16.0 commercial software and compare their performances in terms of cost, responsiveness, transportation frequency, inventory held, etc. The results show that, by the implementation of a well-designed lateral inventory share policy, an omni-channel network can benefit from decreased holding cost and transportation cost, contributing to the CE concept. Full article
(This article belongs to the Special Issue Circular Economy in the Digital Age)
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<p>Circular economy (CE) concept.</p>
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<p>Contribution of lateral inventory share applications towards CE concept (Source: Authors).</p>
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<p>The studied omni-channel system (Source: Authors).</p>
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<p>Simulation model flow-chart with lateral inventory share.</p>
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<p>Simulation model flow-chart with no lateral inventory share.</p>
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<p>Replenishment policy.</p>
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<p>Connectedness level between stores under Policy 1 (Source: Authors).</p>
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<p>Pseudo-codes of Policy 3.</p>
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<p>Connectedness level between stores for Policy 4 (Source: Authors).</p>
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<p>The connection between depots for online policy 5 (Source: Authors).</p>
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<p>OptQuest screenshots: (<b>a</b>) Visualized (<span class="html-italic">s</span>, <span class="html-italic">S</span>) values for results; (<b>b</b>) part where the specified constraints are defined; (<b>c</b>) control part of the decision variables (Source: Authors).</p>
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<p>Optimal total costs versus policies based on <span class="html-italic">LS<sub>C</sub></span> values.</p>
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<p>Total transportation cost under optimal total cost.</p>
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<p>Total holding cost under optimal cost.</p>
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16 pages, 4616 KiB  
Article
Effect of Hydrogen Addition on the Energetic and Ecologic Parameters of an SI Engine Fueled by Biogas
by Saugirdas Pukalskas, Donatas Kriaučiūnas, Alfredas Rimkus, Grzegorz Przybyła, Paweł Droździel and Dalibor Barta
Appl. Sci. 2021, 11(2), 742; https://doi.org/10.3390/app11020742 - 14 Jan 2021
Cited by 33 | Viewed by 3510
Abstract
The global policy solution seeks to reduce the usage of fossil fuels and greenhouse gas (GHG) emissions, and biogas (BG) represents a solutions to these problems. The use of biogas could help cope with increased amounts of waste and reduce usage of fossil [...] Read more.
The global policy solution seeks to reduce the usage of fossil fuels and greenhouse gas (GHG) emissions, and biogas (BG) represents a solutions to these problems. The use of biogas could help cope with increased amounts of waste and reduce usage of fossil fuels. Biogas could be used in compressed natural gas (CNG) engines, but the engine electronic control unit (ECU) needs to be modified. In this research, a spark ignition (SI) engine was tested for mixtures of biogas and hydrogen (volumetric hydrogen concentration of 0, 14, 24, 33, and 43%). In all experiments, two cases of spark timing (ST) were used: the first for an optimal mixture and the second for CNG. The results show that hydrogen increases combustion quality and reduces incomplete combustion products. Because of BG’s lower burning speed, the advanced ST increased brake thermal efficiency (BTE) by 4.3% when the engine was running on biogas. Adding 14 vol% of hydrogen (H2) increases the burning speed of the mixture and enhances BTE by 2.6% at spark timing optimal for CNG (CNG ST) and 0.6% at the optimal mixture ST (mixture ST). Analyses of the rate of heat release (ROHR), temperature, and pressure increase in the cylinder were carried out using utility BURN in AVL BOOST software. Full article
(This article belongs to the Special Issue Advanced Engine Technologies and Innovative Vehicle Driving Systems)
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<p>(<b>a</b>) Change in the number of biogas plants in Europe. (<b>b</b>) Distribution of biogas plants per 1 million people [<a href="#B29-applsci-11-00742" class="html-bibr">29</a>].</p>
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<p>The experimental test rig [<a href="#B56-applsci-11-00742" class="html-bibr">56</a>].</p>
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<p>Change in the brake-specific energy consumption (BSEC) and brake thermal efficiency (BTE) depending on the volumetric fraction of hydrogen and spark timing.</p>
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<p>Change in exhaust gas temperature (T<sub>exh</sub>) and specific emission of nitrogen oxides (NO<sub>x</sub>) depending on the volumetric fraction of hydrogen and spark timing.</p>
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<p>Change in the specific emissions of unburned hydrocarbons (HC) and carbon dioxide (CO<sub>2</sub>) depending on the volumetric fraction of hydrogen and spark timing.</p>
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<p>Pressure in the cylinder (p<sub>cyl</sub>) depending on hydrogen concentration. (<b>A</b>)—with optimal ST for the mixture; (<b>B</b>)—with optimal CNG ST.</p>
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<p>Rate of heat release (ROHR) in the cylinder depending on hydrogen concentration. (<b>A</b>)—with optimal ST for the mixture; (<b>B</b>)—with optimal CNG ST.</p>
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<p>Temperature rise in the cylinder depending on hydrogen concentration. (<b>A</b>)—with optimal ST for the mixture; (<b>B</b>)—with optimal CNG ST.</p>
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<p>Energy distribution. (<b>A</b>)—with optimal ST for the mixture; (<b>B</b>)—with optimal CNG ST.</p>
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17 pages, 3481 KiB  
Article
A Software Reliability Model Considering the Syntax Error in Uncertainty Environment, Optimal Release Time, and Sensitivity Analysis
by Da Hye Lee, In Hong Chang, Hoang Pham and Kwang Yoon Song
Appl. Sci. 2018, 8(9), 1483; https://doi.org/10.3390/app8091483 - 28 Aug 2018
Cited by 18 | Viewed by 2880
Abstract
The goal set by software developers is to develop high quality and reliable software products. During the past decades, software has become complex, and thus, it is difficult to develop stable software products. Software failures often cause serious social or economic losses, and [...] Read more.
The goal set by software developers is to develop high quality and reliable software products. During the past decades, software has become complex, and thus, it is difficult to develop stable software products. Software failures often cause serious social or economic losses, and therefore, software reliability is considered important. Software reliability growth models (SRGMs) have been used to estimate software reliability. In this work, we introduce a new software reliability model and compare it with several non-homogeneous Poisson process (NHPP) models. In addition, we compare the goodness of fit for existing SRGMs using actual data sets based on eight criteria. The results allow us to determine which model is optimal. Full article
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<p>Testing time infrastructure.</p>
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<p>Confidence interval of the new proposed model for data set 1.</p>
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<p>Confidence interval of the new proposed model for data set 2.</p>
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<p>m(t) of all SRGMs for data set 1.</p>
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<p>m(t) of all SRGMs for data set 2.</p>
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<p>System development lifecycle.</p>
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<p><math display="inline"><semantics> <mrow> <msup> <mi mathvariant="normal">T</mi> <mo>*</mo> </msup> </mrow> </semantics></math> and <math display="inline"><semantics> <mrow> <mi mathvariant="normal">C</mi> <mrow> <mo>(</mo> <mi mathvariant="normal">T</mi> <mo>)</mo> </mrow> </mrow> </semantics></math> for <math display="inline"><semantics> <mrow> <msub> <mi mathvariant="normal">T</mi> <mi mathvariant="normal">w</mi> </msub> <mtext> </mtext> </mrow> </semantics></math>(<a href="#applsci-08-01483-t009" class="html-table">Table 9</a>).</p>
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<p><math display="inline"><semantics> <mrow> <msup> <mi mathvariant="normal">T</mi> <mo>*</mo> </msup> </mrow> </semantics></math> and <math display="inline"><semantics> <mrow> <mi mathvariant="normal">C</mi> <mrow> <mo>(</mo> <mi mathvariant="normal">T</mi> <mo>)</mo> </mrow> </mrow> </semantics></math> for <math display="inline"><semantics> <mrow> <msub> <mi mathvariant="normal">T</mi> <mi mathvariant="normal">w</mi> </msub> <mo>=</mo> <mn>10</mn> </mrow> </semantics></math> (<a href="#applsci-08-01483-t010" class="html-table">Table 10</a>).</p>
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<p><math display="inline"><semantics> <mrow> <msup> <mi mathvariant="normal">T</mi> <mo>*</mo> </msup> </mrow> </semantics></math> and <math display="inline"><semantics> <mrow> <mi mathvariant="normal">C</mi> <mrow> <mo>(</mo> <mi mathvariant="normal">T</mi> <mo>)</mo> </mrow> </mrow> </semantics></math> for <math display="inline"><semantics> <mrow> <msub> <mi mathvariant="normal">T</mi> <mi mathvariant="normal">w</mi> </msub> <mo>=</mo> <mn>10</mn> </mrow> </semantics></math> (<a href="#applsci-08-01483-t011" class="html-table">Table 11</a>).</p>
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<p><math display="inline"><semantics> <mrow> <msup> <mi mathvariant="normal">T</mi> <mo>*</mo> </msup> </mrow> </semantics></math> and <math display="inline"><semantics> <mrow> <mi mathvariant="normal">C</mi> <mrow> <mo>(</mo> <mi mathvariant="normal">T</mi> <mo>)</mo> </mrow> </mrow> </semantics></math> for <math display="inline"><semantics> <mrow> <msub> <mi mathvariant="normal">T</mi> <mi mathvariant="normal">w</mi> </msub> <mo>=</mo> <mn>10</mn> </mrow> </semantics></math> (<a href="#applsci-08-01483-t012" class="html-table">Table 12</a>).</p>
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<p><math display="inline"><semantics> <mrow> <msup> <mi mathvariant="normal">T</mi> <mo>*</mo> </msup> </mrow> </semantics></math> and <math display="inline"><semantics> <mrow> <mi mathvariant="normal">C</mi> <mrow> <mo>(</mo> <mi mathvariant="normal">T</mi> <mo>)</mo> </mrow> </mrow> </semantics></math> for <math display="inline"><semantics> <mrow> <msub> <mi mathvariant="normal">T</mi> <mi mathvariant="normal">w</mi> </msub> <mo>=</mo> <mn>10</mn> </mrow> </semantics></math> (<a href="#applsci-08-01483-t013" class="html-table">Table 13</a>).</p>
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<p>Sensitivity analysis for parameters of the optimal release time.</p>
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8529 KiB  
Article
An NHPP Software Reliability Model with S-Shaped Growth Curve Subject to Random Operating Environments and Optimal Release Time
by Kwang Yoon Song, In Hong Chang and Hoang Pham
Appl. Sci. 2017, 7(12), 1304; https://doi.org/10.3390/app7121304 - 16 Dec 2017
Cited by 28 | Viewed by 5387
Abstract
The failure of a computer system because of a software failure can lead to tremendous losses to society; therefore, software reliability is a critical issue in software development. As software has become more prevalent, software reliability has also become a major concern in [...] Read more.
The failure of a computer system because of a software failure can lead to tremendous losses to society; therefore, software reliability is a critical issue in software development. As software has become more prevalent, software reliability has also become a major concern in software development. We need to predict the fluctuations in software reliability and reduce the cost of software testing: therefore, a software development process that considers the release time, cost, reliability, and risk is indispensable. We thus need to develop a model to accurately predict the defects in new software products. In this paper, we propose a new non-homogeneous Poisson process (NHPP) software reliability model, with S-shaped growth curve for use during the software development process, and relate it to a fault detection rate function when considering random operating environments. An explicit mean value function solution for the proposed model is presented. Examples are provided to illustrate the goodness-of-fit of the proposed model, along with several existing NHPP models that are based on two sets of failure data collected from software applications. The results show that the proposed model fits the data more closely than other existing NHPP models to a significant extent. Finally, we propose a model to determine optimal release policies, in which the total software system cost is minimized depending on the given environment. Full article
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<p>System cost model infrastructure.</p>
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<p>Mean value function of the ten models for DS1.</p>
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<p>Mean value function of the ten models for DS2.</p>
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<p>Mean value function of the ten models for DS3.</p>
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<p>95% confidence limits of the newly proposed model for DS1.</p>
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<p>95% confidence limits of the newly proposed model for DS2.</p>
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<p>95% confidence limits of the newly proposed model for DS3.</p>
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<p>Relative error of the ten models for DS1.</p>
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<p>Relative error of the ten models for DS2.</p>
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<p>Relative error of the ten models for DS3.</p>
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<p>Expected total cost for the baseline case.</p>
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<p>Expected total cost subject to the warranty period for the 1st condition.</p>
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<p>Expected total cost subject to the warranty period for the 2nd condition.</p>
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<p>Expected total cost subject to the warranty period for the 3rd condition.</p>
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<p>Expected total cost according to cost coefficient C<sub>2</sub> for the 2nd condition.</p>
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<p>Expected total cost according to cost coefficient C<sub>4</sub> for the 1st condition.</p>
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<p>Expected total cost according to cost coefficient C<sub>4</sub> for the 2nd condition.</p>
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<p>Expected total cost according to cost coefficient C<sub>4</sub> for the 3rd condition.</p>
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