A new bounding mechanism for the CNC machine scheduling problems with controllable processing times

Cataloged from PDF version of article.In this study, we determine the upper and lower bounds for the processing time of each job under controllable machining conditions. The proposed bounding scheme is used to find a set of discrete efficient points on the efficient frontier for a bi-criteria scheduling problem on a single CNC machine. We have two objectives; minimizing the manufacturing cost (comprised of machining and tooling costs) and minimizing makespan. The technological restrictions of the CNC machine along with the job specific parameters affect the machining conditions; such as cutting speed and feed rate, which in turn specify the processing times and tool lives. Since it is well known that scheduling problems are extremely sensitive to processing time data, system resources can be utilized much more efficiently by selecting processing times appropriately. 2004 Elsevier B.V. All rights reserved

Scheduling with tool changes to minimize total completion time under controllable machining conditions

Cataloged from PDF version of article.Scheduling under controllable machining conditions has been studied for some time. Scheduling with tool changes, particularly due to tool wear, has just begun to receive attention. Though machining conditions impact tool wear and induce tool change, the two issues have not been considered together.We address for the first time the problem of scheduling a computer numerically controlled (CNC) machine subject to tool changes and controllable machining conditions; our objective is to minimize the total completion time of a given set of jobs. We establish an important result that helps us identify feasible settings of machining parameters such as feed rate and cutting speed. However, the problem at hand remains intractable, even when a single setting is used. In the general case, we are able to solve the problem exactly for up to 30 jobs using a mixed integer linear programming formulation. For larger problems, we turn to approximate solution via heuristics. We examine a number of different schemes. The best of these schemes are used in a problem space genetic algorithm; this produces quality solutions in a time-efficient manner, as is evidenced from an extensive computational study conducted by us. 2005 Elsevier Ltd. All rights reserved

PENINGKATAN HASIL BELAJAR SISWA DALAM MATA PELAJARAN SEJARAH MELALUI PENERAPAN MODEL PEMBELAJARAN GENIUS LEARNING PADA SISWA KELAS XI IPA 1 SMA NEGERI RAMBIPUJI SEMESTER GENAP TAHUN AJARAN 2010/2011

Abstract: the purpose of this study is to know how the application of genius learning is improving student achievements. The research method is a classroom action research. The result  shows than the genius learning can improve the student achievements. Key Words : Genius Learning, Students Achievemen

KEHIDUPAN SOSIAL-EKONOMI BURUH PERKEBUNAN KALITENGAH TAHUN 1982-2010

Abstract. The aim ofthis research is to identify the social-economic structureof the Kalitengah Plantation labour and to reveal the motive of Kalitengah Plantation labour still loyal toKalitengah Plantation as labour despite in low-wage by using historical methodand structural functional teory. The result of this research shows that there are an internal and external motive that makethe labour of Kalitengah Plantation still loyal to the Kalitengah Plantation. Key Words : social-economiclife, Kalitengah Plantation labour, structural functiona

SITUS DUPLANG DI DESA KAMAL KECAMATAN ARJASA KABUPATEN JEMBER : HISTORISITAS DAN PEMANFAATANNYA SEBAGAI SUMBER PEMBELAJARAN SEJARAH

Abstract : Duplang site in Jember regency has a historical value high enough so it can be              used as a source of historical learning. This research is aimed to examine and describe the historiaty and use the Duplang Site as a source of historical learning with using historical methode. Analysis and interpretation result prove that prehistoric relics on the Duplang Site has a historical value. It can be known by the historic period in Kamal village was in habited by early humans. With the objects of  prehistoric relics on the Duplang Site it can be used as a medium of teaching history. Key Words: History, Advantag

KAJIAN HISTORIS TENTANG CANDI BADUT DI KABUPATEN MALANG

Abstract : The purpose of this study was to identify the historical temple in Malang Regency clown as a place of Reshi Agastya pendarmaan which was built by the Licwa / Gajayana who ruled the kingdom Gajayana langgam Central Java but geographically located in East Java. The results of this study indicate that there is a motive of political upheaval in Central Java which makes a style temple Clown no influence of style temple in Central Java.   Key Words : Temple clowns, poor districts, style templ

PENERAPAN STRATEGI INQUIRI DALAM PEMBELAJARAN SEJARAH UNTUK MENINGKATKAN HASIL BELAJAR SISWA KELAS XI IPS 1 DI SMA NEGERI 1 LAPE KABUPATEN SUMBAWA PROPINSI NTB TAHUN AJARAN 2011-2012

Abstract.Education issomethingvery important foreveryhuman being. The quality ofthelearningcan be improvedin many ways. One way is to usethe rightstrategies and methodsin teaching.This study aimscanimprove student learning outcomesusinginquirystrategy. This research method is a class action research.The results ofthe analysisprove thatinquirystrategiesto improvestudent learning outcomes. Key Words: Education, Inquiry

Considering embodied energy and carbon in heritage buildings – a review

Approximately 20% of UK buildings can be defined as ‘heritage buildings’, offering unique values that should be preserved. They tend to use more energy than newer buildings, creating a strong case for energy retrofits to reduce energy use, greenhouse gas emissions, and improve thermal comfort. However, few studies of heritage retrofits examine embodied impacts, which are the energy and carbon impacts required to manufacture, transport and construct materials and components. This study considers the whole life (embodied plus operational) impacts of retrofitting heritage buildings, through a systematic literature review and thematic analysis. It concludes that; both embodied and operational impacts should be considered in retrofitting projects, retrofitting is better than demolish and rebuild in lifecycle terms, there is a lack of policy mandating for the measurement of lifecycle impacts and low impact retrofitting can be better for conserving heritage values and reducing embodied carbon

COVID-19 vaccine perceptions and uptake in a national prospective cohort of essential workers

INTRODUCTION: In a multi-center prospective cohort of essential workers, we assessed knowledge, attitudes, and practices (KAP) by vaccine intention, prior SARS-CoV-2 positivity, and occupation, and their impact on vaccine uptake over time. METHODS: Initiated in July 2020, the HEROES-RECOVER cohort provided socio-demographics and COVID-19 vaccination data. Using two follow-up surveys approximately three months apart, COVID-19 vaccine KAP, intention, and receipt was collected; the first survey categorized participants as reluctant, reachable, or endorser. RESULTS: A total of 4,803 participants were included in the analysis. Most (70%) were vaccine endorsers, 16% were reachable, and 14% were reluctant. By May 2021, 77% had received at least one vaccine dose. KAP responses strongly predicted vaccine uptake, particularly positive attitudes about safety (aOR = 5.46, 95% CI: 1.4-20.8) and effectiveness (aOR = 5.0, 95% CI: 1.3-19.1). Participants' with prior SARS-CoV-2 infection were 22% less likely to believe the COVID-19 vaccine was effective compared with uninfected participants (aOR 0.78, 95% CI: 0.64-0.96). This was even more pronounced in first responders compared with other occupations, with first responders 42% less likely to believe in COVID-19 vaccine effectiveness (aOR = 0.58, 95% CI 0.40-0.84). Between administrations of the two surveys, 25% of reluctant, 56% reachable, and 83% of endorser groups received the COVID-19 vaccine. The reachable group had large increases in positive responses for questions about vaccine safety (10% of vaccinated, 34% of unvaccinated), and vaccine effectiveness (12% of vaccinated, 27% of unvaccinated). DISCUSSION: Our study demonstrates attitudes associated with COVID-19 vaccine uptake and a positive shift in attitudes over time. First responders, despite potential high exposure to SARS-CoV-2, and participants with a history of SARS-CoV-2 infection were more vaccine reluctant. CONCLUSIONS: Perceptions of the COVID-19 vaccine can shift over time. Targeting messages about the vaccine's safety and effectiveness in reducing SARS-CoV-2 virus infection and illness severity may increase vaccine uptake for reluctant and reachable participants