scholarly journals A cost-aware logical framework

2022 ◽  
Vol 6 (POPL) ◽  
pp. 1-31
Author(s):  
Yue Niu ◽  
Jonathan Sterling ◽  
Harrison Grodin ◽  
Robert Harper

We present calf , a c ost- a ware l ogical f ramework for studying quantitative aspects of functional programs. Taking inspiration from recent work that reconstructs traditional aspects of programming languages in terms of a modal account of phase distinctions , we argue that the cost structure of programs motivates a phase distinction between intension and extension . Armed with this technology, we contribute a synthetic account of cost structure as a computational effect in which cost-aware programs enjoy an internal noninterference property: input/output behavior cannot depend on cost. As a full-spectrum dependent type theory, calf presents a unified language for programming and specification of both cost and behavior that can be integrated smoothly with existing mathematical libraries available in type theoretic proof assistants. We evaluate calf as a general framework for cost analysis by implementing two fundamental techniques for algorithm analysis: the method of recurrence relations and physicist’s method for amortized analysis . We deploy these techniques on a variety of case studies: we prove a tight, closed bound for Euclid’s algorithm, verify the amortized complexity of batched queues, and derive tight, closed bounds for the sequential and parallel complexity of merge sort, all fully mechanized in the Agda proof assistant. Lastly we substantiate the soundness of quantitative reasoning in calf by means of a model construction.

Author(s):  
Mohammad Istiak Hossain ◽  
Jan I. Markendahl

AbstractSmall-scale commercial rollouts of Cellular-IoT (C-IoT) networks have started globally since last year. However, among the plethora of low power wide area network (LPWAN) technologies, the cost-effectiveness of C-IoT is not certain for IoT service providers, small and greenfield operators. Today, there is no known public framework for the feasibility analysis of IoT communication technologies. Hence, this paper first presents a generic framework to assess the cost structure of cellular and non-cellular LPWAN technologies. Then, we applied the framework in eight deployment scenarios to analyze the prospect of LPWAN technologies like Sigfox, LoRaWAN, NB-IoT, LTE-M, and EC-GSM. We consider the inter-technology interference impact on LoRaWAN and Sigfox scalability. Our results validate that a large rollout with a single technology is not cost-efficient. Also, our analysis suggests the rollout possibility of an IoT communication Technology may not be linear to cost-efficiency.


2021 ◽  
Vol 30 (3) ◽  
pp. 1-56
Author(s):  
Mouna Abidi ◽  
Md Saidur Rahman ◽  
Moses Openja ◽  
Foutse Khomh

Nowadays, modern applications are developed using components written in different programming languages and technologies. The cost benefits of reuse and the advantages of each programming language are two main incentives behind the proliferation of such systems. However, as the number of languages increases, so do the challenges related to the development and maintenance of these systems. In such situations, developers may introduce design smells (i.e., anti-patterns and code smells) which are symptoms of poor design and implementation choices. Design smells are defined as poor design and coding choices that can negatively impact the quality of a software program despite satisfying functional requirements. Studies on mono-language systems suggest that the presence of design smells may indicate a higher risk of future bugs and affects code comprehension, thus making systems harder to maintain. However, the impact of multi-language design smells on software quality such as fault-proneness is yet to be investigated. In this article, we present an approach to detect multi-language design smells in the context of JNI systems. We then investigate the prevalence of those design smells and their impacts on fault-proneness. Specifically, we detect 15 design smells in 98 releases of 9 open-source JNI projects. Our results show that the design smells are prevalent in the selected projects and persist throughout the releases of the systems. We observe that, in the analyzed systems, 33.95% of the files involving communications between Java and C/C++ contain occurrences of multi-language design smells. Some kinds of smells are more prevalent than others, e.g., Unused Parameters , Too Much Scattering , and Unused Method Declaration . Our results suggest that files with multi-language design smells can often be more associated with bugs than files without these smells, and that specific smells are more correlated to fault-proneness than others. From analyzing fault-inducing commit messages, we also extracted activities that are more likely to introduce bugs in smelly files. We believe that our findings are important for practitioners as it can help them prioritize design smells during the maintenance of multi-language systems.


1968 ◽  
Vol 6 ◽  
pp. 122
Author(s):  
Peter A. Firmin ◽  
Seymour S. Goodman ◽  
Thomas E. Hendricks ◽  
James J. Linn

Author(s):  
A. A. Golikov ◽  
◽  
J. A. Oleynik

Bridges located on maritime and inland waterways are defenseless objects of infrastructure. One of their main features is the restriction of navigation channels, both vertically and horizontally, while navigation conditions may often be challenged by unpredictable currents and whirlpools. A great threat to people and vehicles on or near the structure occurred in case of a collision with ships and the destruction of bridges. Also, the consequences of such accidents are considerable financial expenses, where the cost of the bridge is usually much more than the cost of the vessel itself. The article addresses the issue of types, factors, causes and consequences of ship-bridge collision accidents. In spite of the modern level of development in the maritime industry such accidents occur annually, thus this problem is considered to be relevant nowadays. It is necessary to take measures to increase the safety of navigation in appropriate zones. The article presents the procedure for assessing the level of safety and the stages of identifying risks by determining the probability of a collision with bridge spans, supports and other structures, also identifying the most defenseless places, as well as the possible consequences of such damage (ship, city, environment). In addition, the paper considered the methods of protecting the bridge from collision and methods for reducing navigational risk. The results of the research are the development of the recommendations for avoiding possible dangers, mitigation of consequences, and reducing risks of vessel-bridge collision. It is proposed to form an “intellectual” zone in the navigable water area under the bridge to minimize the risks and consequences of an emergency. As a basic concept, it is recommended to use foreign and domestic experience in implementing the e-navigation strategy in the coastal zone and in the operational VTS areas. The article describes the implementation of modern marine technologies, such as virtual navigation aids and technologies of additional reality, which will significantly improve monitoring of the environment. Therefore, this introduction will reduce the risk of an emergency. Ensuring the full spectrum of available methods is necessary to determine risk and protect bridges from accidents. Such an approach shall allow not only to assess the risk of ship-bridge collision, but also to introduce additional active control elements during navigation in dangerous zones.


2019 ◽  
Vol 4 (1) ◽  
Author(s):  
NFn Wasita, M.A.

Sebagian rangkaian aktivitas ziarah di beberapa situs arkeologi di KabupatenTapin dan Hulu Sungai Utara, Kalimantan Selatan menunjukkan adanya perilaku dan situasi di tempat ziarah yang mendukung kegiatan pelestarian tinggalan arkeologi. Oleh karena itu, peluang ini perlu dimanfaatkan agar pihak arkeologi mendapatkan cara pelestarian yang melibatkan masyarakat dan murah biayanya. Berkaitan dengan itu, maka penelitian ini ditujukan untuk menemukan cara dalam memanfaatkan perilaku dan situasi untuk pelestarian tinggalan arkeologi dengan tidak mengganggu kegiatan ziarah, namun kegiatan pelestarian yang diinginkan dapat dipertanggungjawabkan secara keilmuan (arkeologi). Penelitian ini dilakukan dengan menggunakan metode deskriptif. Implementasinya di lapangan dilakukan dengan mendeskripsikan tinggalan arkeologi untuk mengetahui kondisi eksistingnya dan riwayat pemugaran yang pernah dilakukan. Pendeskripsian ini untuk mengetahui hal-hal apa saja yang dapat dimanfaatkan dalam mendukung kegiatan pelestarian. Hasil yang diperoleh menunjukkan bahwa di situs-situs arkeologi yang diziarahi terdapat situasi dan perilaku para peziarah yang mendukung kegiatan pelestarian, seperti harus bersikap sopan, tidak merusak barang-barang yang ada di tempat ziarah (dalam konteks ini termasuk tinggalan arkeologi) dan situasi di tempat ziarah yang sakral, serta adanya teguran dari orang yang hidup di alam sebelah jika tidak sopan atau melanggar tata cara ziarah. Jadi kesimpulannya, situasi dan perilaku tersebut perlu dimanfaatkan untuk mendukung pelestarian tinggalan arkeologi. Caranya dengan memberi dukungan, karena perilaku yang baik (tidak merusak warisan budaya) merupakan bagian dari isi undang-undang cagar budaya. Selain itu, juga menghormati situasi yang tercipta di tempat ziarah karena itu merupakan pemaknaan oleh sebagian masyarakat. Agar cara mendukung dan menghormati dapat dipertanggungjawabkan, arkeolog harus jujur dan netral dalam kegiatan pelestarian.Kata kuci: tinggalan arkeologi, ziarah, situasi, perilaku, pelestarianSome parts of pilgrimage activities at several archeological sites in Tapin and Hulu Sungai Utara Districts indicate the existence of behaviors and conditions that support the conservation of archeological remains. This opportunity needs to be utilized, therefore the archeological party can obtain conservation methods that involve the community and the cost is cheap. The research goal is to gain proper method on utilizing pilgrim behaviors and situation for preserving archeological remains without interfering the pilgrimage activities, but the desired of conservation activities can be scientifically accounted (archeology). This research was conducted by using descriptive methods. Its implementation in the field was carried out by describing the archaeological remains of the existing conditions and the history of restoration that had been carried out. The describing of the pilgrim behaviors and the place conditions of pilgrimage is to find out what things can be utilized in supporting conservation activities. The results indicate that at the visited archeological sites there are conditions and behavior of pilgrims who supported conservation activities, such as having to be polite, not damage the items that are in the place of pilgrimage (in this context including archeological remains) and the situation in the sacred place of pilgrimage, as well as the rebuke of people living in the adjoining realm if they are not polite or violate to the procedure of pilgrimage. It is concluded that the situation and behavior need to be used to support the preservation of archeological remains. The way is by giving support, because good behavior (not damaging cultural heritage) is part of the contents of the cultural heritage law. In addition, it also respects the situation created in the place of pilgrimage because it is a meaning by some people. In order to be able to support and respect ways, archaeologists must be honest and neutral in conservation activities.Keywords: archaeological remains, pilgrimage, situations, behavior, preservation.


2021 ◽  
Author(s):  
Schuyler D. Smith ◽  
Jin Choi ◽  
Nicole Ricker ◽  
Fan Yang ◽  
Shannon Hinsa-Leasure ◽  
...  

Effective monitoring of antibiotic resistance genes and their dissemination in environmental ecosystems has been hindered by the cost and efficiency of methods available for the task. We developed a method entitled the Diversity of Antibiotic Resistance genes and Transfer Elements-Quantitative Monitoring (DARTE-QM), a system implementing high-throughput sequencing to simultaneously sequence thousands of antibiotic resistant genes representing a full-spectrum of antibiotic resistance classes commonly seen in environmental systems. In this study, we demonstrated DARTE-QM by screening 662 antibiotic resistance genes within environmental samples originated from manure, soil, and animal feces, in addition to a mock-community used as a control to test performance. DARTE-QM offers a new approach to studying antibiotic resistance in environmental microbiomes, showing advantages in efficiency and the ability to scale for many samples. This method provides a means of data acquisition that will alleviate the obstacles that many researchers in this area currently face.


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