Garbage Collection

Traditional dynamic memory management techniques for imperative programming languages are unsuitable for reliable real-time applications because their worst-case time and space requirements are insufficiently bounded. This is demonstrated by detailed measurements of several real-world workloads. A special hardwareassisted real-time garbage collection system has been designed to facilitate reliable use of dynamic memory in hard real-time systems. By analyzing the dynamic memory use of application software, the real-time developer can prove compliance with time and space constraints. Analysis techniques are presented and the real-time performance of the hardware-assisted garbage collection system is compared to that of traditional allocators. Disciplines

Background: Society, as a whole, regards rag pickers as antisocial elements, an embarrassment to the community, and unfits to live. However, their useful contribution to society and ecology is little understood and generally ignored. The waste collected by these women is recycled and produces 25% of the paper, the packing materials, egg trays, plastic and metal household items, etc., used in homes. This benefits the society and world-ecology enormously by the production of cheaper household goods, and the slowing down of the destruction of the already threatened forests.
Objectives: To study the socio-economic condition of women rag pickers in the present-day scenario. To understand the health problems of women rag pickers. To examine the earning, spending and debt patterns of women rag pickers. Methods: The present study is based on primary and secondary data. The primary data have been collected from three towns of Warangal, Karimnagar and Khammam of Telangana State, India and the sample of the study comprised of 100 rag pickers and selected purposively by using a snowball sampling technique. Results: Majority of women rag pickers age group 21-30 years, 80 per cent are married, 74 per cent of illiterates, 50 per cent of scheduled caste, 87 per cent belong to the nucleus family, their family size is 5-7 members and 83 per cent staying at small huts. Nearly 68 per cent of women rag pickers income is below Rs.11,000/ per annum. Eighty per cent are in debt. Fifty-two per cent has drawn loan from moneylenders, the purpose of the debt on medical expenses, 90 per cent means of transportation for collecting garbages on foot. Majority of women rag pickers opinion that they do not continue this job for a long period, 85 per cent are facing health problems and 94 per cent also opinion that rag-picking is not an appreciated job. Most of the hazardous content was quite high in developing countries since the regulatory and enforcement system to control such waste disposal is usually not in operating.

We present a novel dynamic analysis technique that finds real deadlocks in multi-threaded programs. Our technique runs in two stages. In the first stage, we use an imprecise dynamic analysis technique to find potential deadlocks in a multi-threaded program by observing an execution of the program. In the second stage, we control a random thread scheduler to create the potential deadlocks with high probability. Unlike other dynamic analysis techniques, our approach has the advantage that it does not give any false warnings. We have implemented the technique in a prototype tool for Java, and have experimented on a number of large multi-threaded Java programs. We report a number of previously known and unknown real deadlocks that were found in these benchmarks.

Internet of Things (IoT) can play a major role in keeping the city of Accra clean, greener, more efficient, and safer. This paper proposed a smart garbage collection on the grounds of level of garbage present in the dustbin. This study tries to present a garbage collection management solution based on providing intelligence to dustbin using IoT prototype with sensors. This system would help to maintain cleanness of the streets of Accra Ghana by sending signals through a sensor to a garbage collection unit alerting this unit of the collection of the garbage as and when the dustbins are full. The extreme programming (XP) method was used in building the system which uses ultrasonic sensors placed in the lids of the bins to detect the garbage level and compare it with the garbage bins depth. The system makes use of AVR family microcontroller, LEDs, a SIM800L GSM/GPRS Module and was powdered by a 12V transformer. It was found out that the use of this system assisted in identifying places or areas where garbage bins are full for collection and disposal. It was also found out that waste management companies that adapted the use of this system were achieving their goals of collecting bins at the right time as compare to companies that were not making use of such technology. It was concluded that waste management companies using the system perform better in terms of picking up bins that were full due to the signals received at any point in time which has made in Accra Ghana a community without garbage bins over flowing with rubbish.

This paper examines and analyses the historical development of Zimbabwean towns and cities with a view to tracing and understanding policy directions, urban spatial development trends and other factors such as population dynamics that may have led to the development of the present-day urban settlements in the country. The paper observes that whilst pre-colonial cities existed during the golden age of the Munhumutapa dynasty and empire, these had no influence on the modern town and city because they were too distant and their experiences had long been lost by the time the colonial town was introduced in the country, some four centuries later. Furthermore the paper observes that whilst policy may easily be changed or even reversed, it is a near impossibility to do the same with the spatial physical developments such as buildings and infrastructure – roads, water reticulation, sewerage reticulation and treatment works, railway lines, telecommunication lines and power lines. As a result...

O presente artigo analisou as circunstancias que levaram a cidade de Antofagasta, capital da Segunda Região no Chile, a uma situação crítica de saúde ambiental e conflito socioambiental. Se analisam as consequências
de como um má gestão dos resíduos sólidos urbanos (RSU) na cidade durante anos, derivou numa crise de saúde pública com presença e aumento de casos de cólera y norovirus. A partir dos fatos surgem movimentos sociais que procuram uma mudança estrutural da gestão do lixo, contrapondo os interesses do poder público. A pesquisa articulou a informação obtida de um levantamento bibliográfico de documentação cientifica, jornalística e a entrevista em profundidade de informante chave, que faz parte dos movimentos sociais aqui mencionados. A discussão pretende ser um aporte com uma visão diferente, a solução de um conflito que ainda esta em curso, dando tanto uma mirada crítica da situação como prática para as propostas, desde uma visão ecológica e social.

THE WORLD BANK were collecting over 1,000 indicators, only three of which were common to all cities. This lack of standardization limits the ability of cities to observe trends, monitor process improvements, establish benchmarks, share best practices, or learn from each other. Moreover, data collection costs are often considerable for municipalities. T he Global City Indicators Program (GCIP) is a decentralized, city-led initiative that enables cities to measure, report, and improve their performance and quality of life, facilitate capacity building, and share best practices through an easy-to-use web portal. GCIP assists cities in providing support to decision makers in making informed policy decisions, in addition to enhancing government accountability to the public. An ISO standard for city indicators, which is currently in development, will facilitate comparability and verification across cities and over time. The GCIP was initiated by the World Bank and its partners and is now run by the Global City Indicators Facility, based at the University of Toronto, which oversees the development of indicators and assists cities to join the Program.

Smart cities integrate multiple mobile or websolutions to build a comfortable human habitation. One of these solutions is to provide an environmentally friendly, efficient and effective garbage management system. The current garbage collection system includes routine garbage trucks doing roundsdaily or weekly, which not only doesn't cover every zone of the city but its completely inefficient use of government resources. The proposed system, where admin manage the garbage app for full online based mointoring and analyze the system. Her admin handle bins, driver, complaints from user and work report from driver. This paper proposes a cost-effective mobile or web based system for the government to utilize available resources to efficiently manage the over whelming amounts of garbage collected each day, while also providing a better solution for the inconvenience of garbage disposal for the citizens. This is done by a driver, app will provide predictive and guide routes generated through for garbage trucks. Then driver update the status of work done will be data collected. An android or web app is developed for the work force and the citizens, which primarily provides the user create complatints available smart bin. I.

Lebanon has witnessed in 2015 a severe trash crisis that had serious health and environmental impacts. Trash crisis has recently evolved, and is mostly related to inefficiency in networking, political leadership, and strategic management system and information flow. Trash crisis can be avoided with effective crisis management plan and waste management strategies. The latter is gaining broader attention , especially in the developing countries, with waste management being not well implemented. Until now, no studies have been conducted to measure and evaluate the impacts of the garbage crisis on the Lebanese tourism industry, which is a main income generator sector. Therefore, this research seeks to examine how tourism organizations, especially hotels as main producer of solid waste, are managing their waste to reduce the impacts of the crisis and to understand visitors' perceptions of solid waste management strategies adopted by hotels. 18 hotels' managers in Beirut were interviewed and 124 questionnaires were filled by hotels' guests, who were randomly selected in different areas of the capital. Results revealed that large hotels tend to effectively manage their solid waste which allowed them to overcome the crisis with minimal negative impacts. For the majority of respondents, selecting hotels is not primarily influenced by the implementation of solid waste management strategies. Moreover, results showed that 46% of respondents have hesitated to visit Lebanon during the crisis.

Public-private partnerships are increasingly being promoted in Tanzania and the central argument of this paper is that institutional framework of a given local authority determines the nature and character of the formation and operational performance of such partnerships. The paper focuses on the public-private partnerships established in the area of solid waste management in the City of Dar-es-Salaam, and more specifically on the incentives, constraints and transaction costs that affect garbage collection and disposal in the City. The paper concludes that there has been noticeable, albeit constrained, improvement in garbage collection and disposal in Dar-es-Salaam. The public-private partnerships would, however, benefit from improvements in by-laws, contractual arrangements, enforcement of by-laws and higher public awareness.

Recent technological advances in the development of flashmemory based devices have consolidated their leadership position as the preferred storage media in the embedded systems market and opened new vistas for deployment in enterprise-scale storage systems. Unlike hard disks, flash devices are free from any mechanical moving parts, have no seek or rotational delays and consume lower power. However, the internal idiosyncrasies of flash technology make its performance highly dependent on workload characteristics. The poor performance of random writes has been a cause of major concern which needs to be addressed to better utilize the potential of flash in enterprise-scale environments. We examine one of the important causes of this poor performance: the design of the Flash Translation Layer (FTL) which performs the virtual-to-physical address translations and hides the erase-before-write characteristics of flash. We propose a complete paradigm shift in the design of the core FTL engine from the existing techniques with our Demand-based Flash Translation Layer (DFTL) which selectively caches page-level address mappings. We develop a flash simulation framework called FlashSim. Our experimental evaluation with realistic enterprise-scale workloads endorses the utility of DFTL in enterprise-scale storage systems by demonstrating: (i) improved performance, (ii) reduced garbage collection overhead and (iii) better overload behavior compared to state-of-the-art FTL schemes. For example, a predominantly random-write dominant I/O trace from an OLTP application running at a large financial institution shows a 78% improvement in average response time (due to a 3-fold reduction in operations of the garbage col-Permission to make digital or hard copies of all or part of this work for personal or classroom use is granted without fee provided that copies are not made or distributed for profit or commercial advantage and that copies bear this notice and the full citation on the first page. To copy otherwise, to republish, to post on servers or to redistribute to lists, requires prior specific permission and/or a fee. disks have already been replaced by flash memory in some consumer devices like music players, PDAs, digital cameras.

While garbage collection's software engineering benefits are indisputable, its performance impact remains controversial. Garbage collection proponents argue that its benefits outweigh its costs, but it is widely believed that garbage collection imposes an unacceptably high runtime and space performance penalty. This paper aims to settle this debate. We present the first empirical comparison of the performance costs of automatic versus explicit memory management in a garbage-collected language. Using a tracing and simulation based oracular memory manager, we execute unaltered Java programs as if they used explicit memory management. We examine the runtime, space consumption and virtual memory footprint of Java benchmarks across a range of general-purpose allocators and both copying and non-copying garbage collectors. We show that, at large heap sizes and under no memory pressure, the runtime performance of some garbage collection algorithms is competitive with the Lea memory allocator and occasionally outperforms it by up to 4%. However, our results confirm that garbage collection requires six times the physical memory to achieve this performance and suffers order-of-magnitude performance penalties when paging occurs.

This paper focuses on the evaluation study of door-to-door Garbage Collection (DDGC) program carried out by the Centre for Social Studies, Surat in 2005. The study was based on the information gathered from 4000 respondents drawn from a cross section of society and interviews with the respective officers, contractors and labourers. It also examined the process of actual transfer of solid waste from the generator to the collector and people’s attitude and perception regarding practices of garbage collection and disposal. [Working Paper No.7].

The effects of offering monetary incentives for performing environmentally desirable behaviours are investigated in the context of a pay-by-weight scheme for garbage collection. Effects on different types of recycling and on the motivation behind recycling are investigated in a field setting based on a random sample ( n = 1,955) drawn from two groups of three matched municipalities, where households in one group pay a fixed fee for garbage collection and in the other a fee depending on the weight of their garbage. The study shows that the latter group delivers more material to recycling and composts more in the garden. A substantial proportion of the effect is mediated through perceived self-efficacy and personal norms. The results are consistent with the proposition that government regulation communicates norms and responsibilities and therefore can enhance internalized motivation in the form of a moral norm.

Since benchmarks drive computer science research and industry product development, which ones we use and how we evaluate them are key questions for the community. Despite complex run-time tradeoffs due to dynamic compilation and garbage collection required for Java programs, many evaluations still use methodolo-gies developed for C, C++, and Fortran. SPEC, the dominant pur-veyor of benchmarks, compounded this problem

Après trois décennies d’une longue déliquescence des services municipaux dans la prise en charge des déchets dans l’espace public, les villes camerounaises de Garoua et Maroua ont vu arriver, avec un certain enthousiasme, la société Hysacam. Première institution à reconnaître, en 2008, la collecte des déchets et l’entretien des espaces publics comme une profession à part entière, méritant salaire et protection sociale sur le long terme, l’entreprise a tenté d’opérer le renversement d’un stigmate historiquement bien implanté dans la région. L’auteure revient sur les enjeux politiques, économiques et sociaux de cette privatisation de la gestion des déchets.

On contemporary cache-coherent Non-Uniform Memory Access (ccNUMA) architectures, applications with a large memory footprint suffer from the cost of the garbage collector (GC), because, as the GC scans the reference graph, it makes many remote memory accesses, saturating the interconnect between memory nodes. We address this problem with NumaGiC, a GC with a mostly-distributed design. In order to maximise memory access locality during collection, a GC thread avoids accessing a different memory node, instead notifying a remote GC thread with a message; nonetheless, NumaGiC avoids the drawbacks of a pure distributed design, which tends to decrease parallelism. We compare NumaGiC with Parallel Scavenge and NAPS on two different ccNUMA architectures running on the Hotspot Java Virtual Machine of OpenJDK 7. On Spark and Neo4j, two industry-strength analytics applications, with heap sizes ranging from 160 GB to 350 GB, and on SPECjbb2013 and SPECjbb2005, Numa-GiC improves overall performance by up to 45% over NAPS (up to 94% over Parallel Scavenge), and increases the performance of the collector itself by up to 3.6× over NAPS (up to 5.4× over Parallel Scavenge).

In this paper, we address the problem of garbage collection in a single-failure fault-tolerant home-based lazy release consistency (HLRC) distributed shared-memory (DSM) system based on independent checkpointing and logging. Our solution uses laziness in garbage collection and exploits consistency constraints of the HLRC memory model for low overhead and scalability. We prove safe bounds on the state that must be retained in the system to guarantee correct recovery after a failure. We devise two algorithms for garbage collection of checkpoints and logs, checkpoint garbage collection (CGC), and lazy log trimming (LLT). The proposed approach targets large-scale distributed shared-memory computing on local-area clusters of computers. In such systems, using global synchronization or extra communication for garbage collection is inefficient or simply impractical due to system scale and temporary disconnections in communication. The challenge lies in controlling the size of the logs and the number of checkpoints without global synchronization while tolerating transient disruptions in communication. Our garbage collection scheme is completely distributed, does not force processes to synchronize, does not add extra messages to the base DSM protocol, and uses only the available DSM protocol information. Evaluation results for real applications show that it effectively bounds the number of past checkpoints to be retained and the size of the logs in stable storage.

There is an emerging class of interactive multimedia applications that deal with stream data from distributed sources. Indexing the data temporally allows for ordering individual streams as well as correlation across streams. Stampede programming system facilitates the organization of stream data into channels, which are distributed, synchronized data structures containing timestamped data. Channels allow multiple threads to produce and consume items in sparse, and out of timestamp order. These flexibilities are required due to the dynamic and parallel structure of applications. Under these circumstances, a key issue is the "garbage collection" of channel items. In this paper we present and compare three different GC algorithms: (1) REF is a simple localized algorithm that keeps a reference count on individual items; (2) TGC, which needs no application knowledge employs a distributed algorithm for computing a low water-mark for timestamp value of interest in the entire application; and (3) DGC, uses an application task graph to determine the relevant timestamps local to each channel and thread. DGC can simultaneously eliminate garbage from channels and unneeded computations from threads. In tests performed using an interactive application, DGC enjoys nearly 30% reduction in the application memory footprint compared to TGC and REF.

The traditional virtual memory system is designed for decades assuming a magnetic disk as the secondary storage. Recently, flash memory becomes a popular storage alternative for many portable devices with the continuing improvements on its capacity, reliability and much lower power consumption than mechanical hard drives. The characteristics of flash memory are quite different from a magnetic disk. Therefore, in this paper, we revisit virtual memory system design considering limitations imposed by flash memory. In particular, we focus on the energy efficient aspect since power is the first-order design consideration for embedded systems. Due to the write-once feature of flash memory, frequent writes incur frequent garbage collection thereby introducing significant energy overhead. Therefore, in this paper, we propose three methods to reduce writes to flash memory. The HotCache scheme adds an SRAM cache to buffer frequent writes. The subpaging technique partitions a page into subunits, and only dirty subpages are written to flash memory. The duplication-aware garbage collection method exploits data redundancy between the main memory and flash memory to reduce writes incurred by garbage collection. We also identify one type of data locality that is inherent in accesses to flash memory in the virtual memory system, intrapage locality. Intrapage locality needs to be carefully maintained for data allocation in flash memory. Destroying intrapage locality causes noticeable increases in energy consumption. Experimental results show that the average energy reduction of combined subpaging, HotCache, and duplication-aware garbage collection techniques is 42.2%.

Region-based memory management can offer improved time performance, relatively good memory locality and reuse, and also provide better adherence to real-time constraints during execution, when compared against traditional garbage collection. We have implemented a region-memory subsystem into the SSCLI 2.0 platform and also adapted an inference system to region-enable CIL programs, with the aid of newly introduced instructions. Results seem promising, as the programs running with regions have considerably smaller interrupting delays, compared to those running with garbage collection. Regions can bring runtime speed improvement of up to 50%, depending on how complicated are the data structures used in execution. The present work can also be viewed as an experience report based on our initiatory attempt at integrating a new region memory subsystem into a commercially developed shared source platform.

Plastic waste which is increasing day by day becomes eyesore and in turn pollutes the environment, especially in high mountain villages where no garbage collection system exists. A large amount of plastic is being brought into the tourist trekking regions are discarded or burned which leads to the contamination of environment and air. Hence, these waste plastics are to be effectively utilized. Low-density polyethylene bags are cleaned and added with sand at particular percentages to obtain high strength bricks that possess thermal and sound insulation properties to control pollution and to reduce the overall cost of construction; this is one of the best ways to avoid the accumulation of plastic waste which is an on-degradable pollutant. This alternatively saves the quantity of sand/clay that has to be taken away from the precious river beds/mines. The plastic waste is naturally available in surplus quantity and hence the cost factor comes down. Also coloring agents can be added to the mixture to attain desired shades. Hence in this thesis, an attempt is made to study regard the properties of the brick which is manufactured using plastic wastes. The present work deals with the manufacturing and analysis of bricks made with waste plastic (LDPE) and fine aggregates. The bricks produced are light weight, have smooth surface and fine edges, do not have cracks and have high crushing strength and very low water absorption. The bricks are manufactured by heating waste plastic to temperature range of 120 to 150 degree centigrade and mixing sand to the molten plastic. I.

The objectives of this background paper are to review past and current experiences in community-based solid waste management and its integration into the formal government system of solid waste management. Many projects have been funded by various organizations, donors and the Government of Indonesia (GOI) and the successes of these in terms of economic benefits and improved environmental health, and for the GOI, will examine. This paper will cover the following aspects: a) information relating to market potential for recycled goods and compost; and b) trends over time and the costs and benefits of changes. Chapter two provides a brief overview of the respective roles played by the formal and informal sector service providers. In chapter three, a chronological presentation is given of the significant initiatives that have facilitated community-based involvement in solid waste management in Indonesia. Chapter four identifies the success and failures, provides an overview of the lesso...

This study aims to examine Mamak Garbage Area and the residents in that neighbourhood within ecophobic discourse in terms of analysing why and how they have become the target of ecophobic psyche. Garbage areas in general constitute elemental bodies combining natural elements and human influences since these areas are human-made natural storage yards. Moreover, junkyards reflect the relationship between human and nonhuman encounters. However, when disastrous results are experienced, human beings simply blame nature itself for the wrongdoings of the human practices. Furthermore, ecophobia is also targeted towards the human bodies residing in the garbage areas and depending on garbage for their living. Moreover, similar to wild nature, those human bodies are also excluded from the civil order, contributing to the discursive deep clash between nature and culture.

Pendidikan adalah bagian yang tidak terpisahkan dari ajaran Islam secara keseluruhan, ia merupakan bagian yang terpadu dari aspek-aspek ajaran Islam. Karena itulah, dalam sejarah dikatakan bahwa Nabi Muhammad saw sangat mementingkan pendidikan. Beliau senantiasa menempatkan pendidikan sebagai sesuatu yang urgen dengan cara mengadakan pengajaran (ta'līm) kepada para sahabatnya supaya mereka memahami ajaran-ajaran Islam secara universal. Upaya Nabi Muhammad saw dalam mengajar sahabat-sahabatnya, sebenarnya menjadi misi utamanya. Misi tersebut sesuai yang terdapat dalam ayat yang pertama kali turun "iqra" perintah membaca.

The availability of high-speed solid-state storage has introduced a new tier into the storage hierarchy. Low-latency and high-IOPS solid-state drives (SSDs) cache data in front of high-capacity disks. However, most existing SSDs are designed to be a drop-in disk replacement, and hence are mismatched for use as a cache.

VIP Dumpster Rental of Austin Texas believes that solid waste management is a problem in our society. The problem becomes worse in areas where there are high concentrations of humanity like Austin. Urban centers come to mind when we look at the challenge. The volumes of garbage produced each day by families and industrial setups have become a significant threat to our environmental habitation (Dunlop, R.E 1991). In light of the enormity of the challenge that the waste collection and disposal poses, it is important that those of us who are environmentally conscious find mechanisms to help alleviate the situation. The team at VIP Dumpster Rental Austin Texas are committed to finding creative solutions to eliminating the chaotic situation.

Java is a strong player in the application server market and thus the performance of its virtual machine is an important aspect of a server's performance. One of the components that affect the performance of a JVM is the memory manager, which also includes the garbage collector. Modern virtual machines offer a multitude of options for tuning the memory manager, which can have a significant impact on server application performance. In this paper, we examine the effect of tuning the garbage collection in an application server ...

Programming distributed applications supporting data sharing is very hard. In most middleware platforms, programmers must deal with system-level issues for which they do not have the adequate knowledge, e.g., object replication, abusive resource consumption by mobile agents, and distributed garbage collection. As a result, programmers are diverted from their main task: the application logic. In addition, given that such system-level issues are extremely error-prone, programmers spend innumerous hours debugging. We designed, implemented, and evaluated a middleware platform called OBIWAN that releases the programmer from the above mentioned system-level issues. OBIWAN has the following distinctive characteristics: 1) allows the programmer to develop applications using either remote object invocation, object replication, or mobile agents, according to the specific needs of applications, 2) supports automatic object replication (e.g., incremental on-demand replication, transparent object faulting and serving, etc.), 3) supports distributed garbage collection of useless replicas, and 4) supports the specification and enforcement of history-based security policies well adapted to mobile agents needs (e.g., preventing abusive resource consumption).