An Exploratory Study on the Characteristics of Logging Practices in Mobile Apps: A Case Study on F-Droid

Logging is a common practice in software engineering. Prior research has investigated the characteristics of logging practices in system software (e.g., web servers or databases) as well as desktop applications. However, despite the popularity of mobile apps, little is known about their logging practices. In this thesis, we sought to study logging practices in mobile apps. In particular, we conduct a case study on 1,444 open source Android apps in the F-Droid repository. Through a quantitative study, we find that although mobile app logging is less pervasive than server and desktop applications, logging is leveraged in almost all studied apps. However, we find that there exist considerable differences between the logging practices of mobile apps and the logging practices in server and desktop applications observed by prior studies. In order to further understand such differences, we conduct a firehouse email interview and a qualitative annotation on the rationale of using logs in mobile app development. By comparing the logging level of each logging statement with developers' rationale of using the logs, we find that all too often (35.4%), the chosen logging level and the rationale are inconsistent. Such inconsistency may prevent the useful runtime information to be recorded or may generate unnecessary logs that may cause performance overhead. Finally, to understand the magnitude of such performance overhead, we conduct a performance evaluation between generating all the logs and not generating any logs in eight mobile apps. In general, we observe a statistically significant performance overhead based on various performance metrics (response time, CPU and battery consumption). In addition, we find that if the performance overhead of logging is significantly observed in an app, disabling the unnecessary logs indeed provides a statistically significant performance improvement. Our results show the need for a systematic guidance and automated tool support to assist in mobile logging practices

How Yoopers see the future of their communities: why residents leave or stay in Michigan\u27s Upper Peninsula

According to a Community and Environment in Rural America survey, Michigan\u27s Upper Peninsula residents, often called Yoopers, said that ties to community and the area\u27s natural beauty were significant factors for those who planned on staying in this rural area, which comprises about a third of Michigan\u27s land mass but only 4 percent of its population. Those planning on leaving cited employment opportunities and energy costs as the most important factors in their decision

MEASURING FOREST RESOURCE VALUES: AN ASSESSMENT OF CHOICE EXPERIMENTS AND PREFERENCE CONSTRUCTION METHODS AS PUBLIC INVOLVEMENT TOOLS

Human values arising from forests include market and non-market values. Timber values and values of non-timber forest products traded in markets (berries, wild rice, etc.) are considered market values. Among non-market values are recreation values and values associated with wildlife harvesting by Aboriginal People. These are considered non-market because participation in these activities does not require the purchase of market based permits; prices do not function as rationing devices in these activities. In addition to non-market values arising from activities, individuals may also have values associated with forest conditions (biodiversity, etc.). These are referred to as passive use values since the value is not associated with any specific use of the resource or activity related to the forest. Since forests in Canada are largely on public land, these passive use values are particularly relevant to Canadian forest management. These values reveal the preferences of the public for components of forest management. Eliciting these values is a form of public involvement in that the public is engaged in assessing forest management options and providing opinions and sentiments regarding these options. Ideally, values arising from forests would be collected from a broad range of the public and examined to provide guidance to forest managers. However, values over forest outputs and conditions may be very poorly formed when people have little experience with the range and complexity of forest ecology and management. In addition, eliciting values without framing them in a trade-off setting can result in misleading estimates. In this project we attempt to elicit passive use values in a manner that allows for poorly defined initial notions of value through an approach known as preference construction. Preference construction essentially provides for education and information processing in the development of passive use values. These estimates are also developed using a trade-off approach (choice experiments). The project focuses on the values of the local public within the NorSask forest. More formally, the objectives of this research are to: 1) ascertain the passive use values held by local people associated with forests in the NorSask Forest Management License Area; 2) explore differences in preferences based on the degree and frequency of formal preference construction exercises; and 3) evaluate this approach as a method of public involvement. A total of 43 individuals from the local community were involved in the valuation exercise. They participated in 3 groups or treatments, each with a different level of involvement in the valuation assessment. The first group was involved in three separate sessions, allowing for significant preference construction and information acquisition. The second group was involved in only one session and the third group was involved only minimally through a telephone contact and the completion of a survey delivered through the mail. The hypothesis being examined was that the degree of involvement in the exercise would affect the responses either in terms of the variances of the responses or the actual preferences. Not all forest values can be examined in a single valuation task. In this case values associated with key game species (moose), wildlife species reflecting biodiversity or threatened species (caribou), old age classes of forest, protected areas and local employment were assessed. These were selected based on the preference construction sessions with the first group. A general trend was found in the ranking of forest values. The values were highest for increases in older forest age classes and protected areas and lower for caribou and moose levels (expressed in percentage changes relative to current levels). The lowest value arose from the local jobs generated by forestry activity. Monetary measures of these values were also developed. The scenario choices made by the individuals revealed that a 5% increase in moose and caribou populations would be worth approximately $10 and$12 per year. A 5% increases in old age classes or protected areas was worth approximately 4 to 5 times as much. They were willing to pay approximately $7 per year in increased taxes for increases in local employment. The hypothesis that the group preferences would differ was not accepted. The preferences of the first and third groups, while expected to be very different, were in fact quite similar. The second group did appear to be different from these other two but it is possible that significant variation in demographic characteristics was driving that difference, rather than the level of preference construction effort. The sample in the third group did however exhibit more resistance to completing the exercise and registered more protests to the value assessment. In conclusion, the approach employed was successful in eliciting passive use values for components of forest management. These values alone provide interesting information for managers to consider in the development of management plans. Evidence supporting the hypothesis that preference construction approaches improve these valuation exercises was not found in this study although this result must be tempered by the limitations arising from sample size and demographic composition of the study groups.Resource /Energy Economics and Policy,

A Tool for Rejuvenating Feature Logging Levels via Git Histories and Degree of Interest

Logging is a significant programming practice. Due to the highly transactional nature of modern software applications, massive amount of logs are generated every day, which may overwhelm developers. Logging information overload can be dangerous to software applications. Using log levels, developers can print the useful information while hiding the verbose logs during software runtime. As software evolves, the log levels of logging statements associated with the surrounding software feature implementation may also need to be altered. Maintaining log levels necessitates a significant amount of manual effort. In this paper, we demonstrate an automated approach that can rejuvenate feature log levels by matching the interest level of developers in the surrounding features. The approach is implemented as an open-source Eclipse plugin, using two external plug-ins (JGit and Mylyn). It was tested on 18 open-source Java projects consisting of ~3 million lines of code and ~4K log statements. Our tool successfully analyzes 99.22% of logging statements, increases log level distributions by ~20%, and increases the focus of logs in bug fix contexts ~83% of the time. For further details, interested readers can watch our demonstration video (https://www.youtube.com/watch?v=qIULoAXoDv4).Comment: 4 pages, ICSE '22 (tool demo track

Log4Perf: Suggesting and Updating Logging Locations for Web-based Systems' Performance Monitoring

Performance assurance activities are an essential step in the release cycle of software systems. Logs have become one of the most important sources of information that is used to monitor, understand and improve software performance. However, developers often face the challenge of making logging decisions, i.e., neither logging too little and logging too much is desirable. Although prior research has proposed techniques to assist in logging decisions, those automated logging guidance techniques are rather general, without considering a particular goal, such as monitoring software performance. In this thesis, we present Log4Perf, an automated approach that provides suggestions of where to insert logging statements with the goal of monitoring web-based systems' software performance. In particular, our approach builds and manipulates a statistical performance model to identify the locations in the source code that statistically significantly influence software performance. To evaluate Log4Perf, we conduct case studies on open source systems, i.e., CloudStore and OpenMRS, and one large-scale commercial system. Our evaluation results show that Log4Perf can build well-fit statistical performance models, indicating that such models can be leveraged to investigate the influence of locations in the source code on performance. Also, the suggested logging locations are often small and simple methods that do not have logging statements and that are not performance hotspots, making our approach an ideal complement to traditional approaches that are based on software metrics or performance hotspots. In addition, we proposed approaches that can suggest the need for updating logging locations when software evolves. After evaluating our approach, we manually examine the logging locations that are newly suggested or deprecated and identify seven root-causes. Log4Perf is integrated into the release engineering process of the commercial software to provide logging suggestions on a regular basis

The visual preferences for forest regeneration and field afforestation : four case studies in Finland

The overall aim of this dissertation was to study the public's preferences for forest regeneration fellings and field afforestations, as well as to find out the relations of these preferences to landscape management instructions, to ecological healthiness, and to the contemporary theories for predicting landscape preferences. This dissertation includes four case studies in Finland, each based on the visualization of management options and surveys. Guidelines for improving the visual quality of forest regeneration and field afforestation are given based on the case studies. The results show that forest regeneration can be connected to positive images and memories when the regeneration area is small and some time has passed since the felling. Preferences may not depend only on the management alternative itself but also on the viewing distance, viewing point, and the scene in which the management options are implemented. The current Finnish forest landscape management guidelines as well as the ecological healthiness of the studied options are to a large extent compatible with the public's preferences. However, there are some discrepancies. For example, the landscape management instructions as well as ecological hypotheses suggest that the retention trees need to be left in groups, whereas people usually prefer individually located retention trees to those trees in groups. Information and psycho-evolutionary theories provide some possible explanations for people's preferences for forest regeneration and field afforestation, but the results cannot be consistently explained by these theories. The preferences of the different stakeholder groups were very similar. However, the preference ratings of the groups that make their living from forest - forest owners and forest professionals - slightly differed from those of the others. These results provide support for the assumptions that preferences are largely consistent at least within one nation, but that knowledge and a reference group may also influence preferences.Väitöskirjassa tutkittiin ihmisten maisemapreferenssejä (maisemallisia arvostuksia) metsänuudistamishakkuiden ja pellonmetsitysten suhteen sekä analysoitiin näiden preferenssien yhteyksiä maisemanhoito-ohjeisiin, vaihtoehtojen ekologiseen terveyteen ja preferenssejä ennustaviin teorioihin. Väitöskirja sisältää neljä tapaustutkimusta, jotka perustuvat hoitovaihtoehtojen visualisointiin ja kyselytutkimuksiin. Tapaustutkimusten pohjalta annetaan ohjeita siitä, kuinka uudistushakkuiden ja pellonmetsitysten visuaalista laatua voidaan parantaa. Väitöskirjan tulokset osoittavat, että uudistamishakkuut voivat herättää myös myönteisiä mielikuvia ja muistoja, jos uudistusala on pieni ja hakkuun välittömät jäljet ovat jo peittyneet. Preferensseihin vaikuttaa hoitovaihtoehdon lisäksi mm. katseluetäisyys, katselupiste ja ympäristö, jossa vaihtoehto on toteutettu. Eri viiteryhmien (metsäammattilaiset, pääkaupunkiseudun asukkaat, ympäristönsuojelijat, tutkimusalueiden matkailijat, paikalliset asukkaat sekä metsänomistajat) maisemapreferenssit olivat hyvin samankaltaisia. Kuitenkin ne ryhmät, jotka saavat ainakin osan elannostaan metsästä - metsänomistajat ja metsäammattilaiset - pitivät metsänhakkuita esittävistä kuvista hieman enemmän kuin muut ryhmät. Nämä tulokset tukevat oletusta, että maisemapreferenssit ovat laajalti yhteneväisiä ainakin yhden kansan tai kulttuurin keskuudessa, vaikka myös viiteryhmä saattaa vaikuttaa preferensseihin jonkin verran. Nykyiset metsämaisemanhoito-ohjeet ovat pitkälti samankaltaisia tässä väitöskirjassa havaittujen maisemapreferenssien kanssa. Myöskään tutkittujen vaihtoehtoisten hoitotapojen ekologisen paremmuuden ja niihin kohdistuvien maisemallisten arvostusten välillä ei ollut suurta ristiriitaa. Kuitenkin joitakin eroavaisuuksia oli; esimerkiksi sekä maisemanhoito-ohjeiden että ekologisten hypoteesien mukaan säästöpuut tulisi jättää ryhmiin, kun taas ihmiset pitivät eniten yksittäin jätetyistä puista. Informaatiomalli ja psyko-evolutionaarinen teoria tarjoavat mahdollisia selityksiä uudistushakkuisiin ja pellonmetsitykseen kohdistuville preferensseille, vaikkakaan tutkimuksen tuloksia ei voida täysin selittää näillä teorioilla

Multiple multimodal mobile devices: Lessons learned from engineering lifelog solutions

For lifelogging, or the recording of one’s life history through digital means, to be successful, a range of separate multimodal mobile devices must be employed. These include smartphones such as the N95, the Microsoft SenseCam – a wearable passive photo capture device, or wearable biometric devices. Each collects a facet of the bigger picture, through, for example, personal digital photos, mobile messages and documents access history, but unfortunately, they operate independently and unaware of each other. This creates significant challenges for the practical application of these devices, the use and integration of their data and their operation by a user. In this chapter we discuss the software engineering challenges and their implications for individuals working on integration of data from multiple ubiquitous mobile devices drawing on our experiences working with such technology over the past several years for the development of integrated personal lifelogs. The chapter serves as an engineering guide to those considering working in the domain of lifelogging and more generally to those working with multiple multimodal devices and integration of their data