Makespan minimization with OR-precedence constraints

We consider a variant of the NP-hard problem of assigning jobs to machines to minimize the completion time of the last job. Usually, precedence constraints are given by a partial order on the set of jobs, and each job requires all its predecessors to be completed before it can start. In this paper, we consider a different type of precedence relation that has not been discussed as extensively and is called OR-precedence. In order for a job to start, we require that at least one of its predecessors is completed—in contrast to all its predecessors. Additionally, we assume that each job has a release date before which it must not start. We prove that a simple List Scheduling algorithm due to Graham (Bell Syst Tech J 45(9):1563–1581, 1966) has an approximation guarantee of 2 and show that obtaining an approximation factor of $$4/3 - \varepsilon $$ 4 / 3 - ε is NP-hard. Further, we present a polynomial-time algorithm that solves the problem to optimality if preemptions are allowed. The latter result is in contrast to classical precedence constraints where the preemptive variant is already NP-hard. Our algorithm generalizes previous results for unit processing time jobs subject to OR-precedence constraints, but without release dates. The running time of our algorithm is $$O(n^2)$$ O ( n 2 ) for arbitrary processing times and it can be reduced to O(n) for unit processing times, where n is the number of jobs. The performance guarantees presented here match the best-known ones for special cases where classical precedence constraints and OR-precedence constraints coincide.

Pemikiran Pendidikan Karakter Ibn Miskawaih (Telaah Filosofis)

This study aims to analyze the concept of character education according to Ibn Miskawaih in a philosophical perspective with a focus on studies from the side of ontology, epistemology, and axiology. The research method used is the library research method. Sources of literature in this study consist of primary sources and secondary sources. The primary source of literature is the book of tahzib al-Akhlak, and the secondary source is references related to character education such as other books from Ibn Miskawaih's essays, journals, or proceedings. Data analysis begins with unit processing, categorization, and ends with data interpretation. The results showed that ontologically, character education is an effort to curb the three forces that exist in the human soul, so that all body activities become good and spontaneous without the need for prior consideration. Epistemologically, the character education method includes willpower, self-introspection, thariqun thabi'iyyah and opposition methods. Axiologically, character education boils down to the middle path (al-wasath), with main virtues such as al-hikmah (wisdom), al-'iffah (maintaining self-purity), as-Saja'ah (courage) and al-'adalah ( justice).

Nilai-Nilai Pendidikan Tasawuf dalam Film “99 Kali Rindu” Karya Azhari Zain

This study aims to (1) determine the meaning of Sufism education; (2) knowing the values ​​of Sufism education contained in the film "99 Kali Rindu"; (3) to determine the relevance of the values ​​of Sufism education in the film "99 Kali Rindu" with Islamic education today. The method used in this data analysis is descriptive analysis method, while the data collection techniques used in this data collection are documentation techniques and library research. The collected data were then analyzed by unit processing. In the film 99 Kali Rindu, after doing the research it can be concluded that: (1) the definition of sufism is the teaching or belief that knowledge of truth and Allah can be achieved by means of mental vision of reflection, (2) the film has sufism educational values ​​that can be applied to students. these values ​​are: (a) divine value (deity), (b) insaniyah (human) values, (c) natural value (nature), (3) the relevance of sufism education in islamic education is that it has a relevant relationship, which is applied to schools and educational institutions. The dialogue excerpt made by Azhari Zain in his film 99 Kali Rindu, contains the values ​​of Sufism education which are in accordance with the material taught at schools and educational institutions such as Akidah Akhlak, Al-Quran Hadith, and other Islamic education. The values ​​in it are very important to be instilled in students, so that they can become a generation that fights for and advances this nation with knowledge and morals

Comparative Assessment of Thermo-Syngas Fermentative and Liquefaction Technologies as Waste Plastics Repurposing Strategies

The present study comparatively investigates the potential of waste plastic utilization as a feedstock for the production of liquid fuels to satisfy the rising liquid fuel demands of the transportation industry while simultaneously resolving the global plastic waste pollution challenge. For the first time, therefore, conceptual models simulating the production of transportation fuels of ethanol and gasoline from waste plastics via the technologies of thermo-syngas fermentation and hydrothermal liquefaction were assessed using classic technoeconomic assessment methods. The conceptual models were developed based on existing experimental data as obtained from the literature and simulated using ASPEN Plus as the preferred process simulation tool. This study demonstrated the technical viability of both conversion pathways with the hydrothermal liquefaction (HTL) of waste plastics for gasoline production shown to constitute a more economically preferable pathway. This was because the HTL of waste plastics presented a higher internal rate of return (IRR) value and a lower unit processing cost of 51.3% and USD 0.38 per kg compared to the thermo-syngas fermentation pathway that presented an IRR value and a unit processing cost value of 22.2% and USD 0.42 per kg, respectively. Payback periods of 5 years and 2 years were also determined as vital to recoup initial capital invested in the thermo-syngas fermentation project and the HTL project, respectively. Therefore, this study provides a basis for further work regarding waste plastic management strategies while offering a useful guide for policy makers in determining the most cost-effective way to utilize waste plastic and thus promote favorable environmental outcomes.