Införandet av ny teknologi i organisationer är ett ständigt aktuellt forskningsområde inom affärssystemforskningen. De senaste åren har fenomenet ”Molntjänster”, eller Software as a Service (SaaS), vuxit i popularitet. Många affärssystemleverantörer erbjuder idag sina kunder affärssystem som en molntjänst. SaaS-baserade affärssystem ger organisationer fördelar i jämförelse med traditionella affärssystem som installeras lokalt i organisationen, som exempelvis ökad skalbarhet, bättre åtkomstmöjligheter, samt lägre kostnader för implementation - vilket gör det särskilt intressant för små och medelstora organisationer. Dock innebär SaaS-baserade affärssystem även risker, som relateras till exempelvis bristande säkerhet, begränsade möjligheter till systemanpassning och integration, bristande prestanda, samt leverantörsinlåsning. Dessa risker kan få organisationer att tveka till att implementera SaaS-baserade affärssystem, trots identifierade fördelar. Tidigare forskning har identifierat både fördelar och risker med SaaS-baserade affärssystem, men lite är känt om varför små och medelstora organisationer väljer att införa sådana system trots de risker systemen är associerade med. Studiens syfte är därför att skapa förståelse för vad som har betydelse för att små och medelstora organisationer implementerar SaaS-baserade affärssystem, trots kända risker. Studiens resultat indikerar att förståelse för risker, tillit och förtroende för systemleverantören, reducerat kompetensbehov internt i organisationer, samt graden av komparativa fördelar har betydelse för organisationers vilja och acceptans till att implementera SaaS-baserade affärssystem, trots risker. Studiens slutsatser har även bidragit med rekommendationer för hur systemleverantörer av SaaS-baserade affärssystem kan utveckla sina värdeerbjudanden. Exempelvis rekommenderas systemleverantörer att vara ärliga och transparenta i kommunikationen mot kundorganisationer, samt att samarbeta med kundorganisationer genom hela implementationsfasen och efter slutförda implementationsprojekt. / The introduction of new technology in organizations is an ever-present area of research within ERP systems research. In recent years, the phenomenon of "Cloud Services", or Software as a Service (SaaS), is growing in popularity. Today, many ERP system suppliers offer their customers ERP systems as a cloud service. SaaS-based ERP systems give organizations advantages over traditional ERP systems that are installed locally in the organization, such as increased scalability, better accessibility, and lower implementation costs - which makes them particularly interesting for small and medium-sized organizations. However, SaaS-based ERP systems also involve risks that are related to, for example, lack of security, limited possibilities for system customization and integration, lack of system performance, and supplier lock-in. These risks may cause organizations to avoid SaaS-based ERP systems, despite identified benefits. Earlier research has identified both benefits and risks with SaaS-based ERP systems, but little is known about why small and medium-sized organizations choose to implement such systems despite the risks associated with them. The aim of the study is therefore to create an understanding of why small and medium-sized organizations choose to implement SaaS-based ERP systems, despite known risks. The study's results indicate that understanding of risks, trust and confidence in the system vendor, reduced internal competence needs, and the level of comparative advantages are important for organizations' willingness and acceptance to implement SaaS-based ERP systems, despite risks. The study’s conclusions also contributed with recommendations for how systems suppliers of SaaS-based ERP systems can develop their value propositions. For example, system suppliers are advised to be honest and transparent in communicating with customer organizations, as well as collaborating with customer organizations throughout the implementation phase and after the completion of implementation projects.

Molntjänster erbjuder skalbara IT-resurser på begäran över internet, där molntjänstanvändaren endast betalar efter förbrukning. Dessa resurser kan variera mellan allt från processorkraft till lagring (Amazon, 2019). Digitaliseringen av samhället har bidragit till en ökad efterfrågan på innovativa lösningar. Detta har resulterat i att molntjänster har ökat i popularitet inom offentlig sektor, exempelvis inom kommunal verksamhet där trenden pekar på att efterfrågan på molntjänster samt användning av molnlösningar fortsätter att öka. När offentliga aktörer väljer att implementera molntjänster så är det viktigt att den information som hanteras av en molntjänst bibehåller en hög nivå av informationssäkerhet (Hellberg, Islam, & Karlsson, 2018). Viktiga aspekter som kommunal verksamhet bör beakta är funktionalitet och juridiska krav. Förutom dessa aspekter så bör molntjänstkunder även ställa tydliga krav på de tekniska utmaningar som existerar för att kunna säkerställa att lösningen som tillhandahålls uppfyller verksamhetens kriterier rörande interoperabilitet och dataportabilitet.  Denna studie har till syfte att utveckla en checklista som kan användas vid upphandling av molntjänster inom kommunal verksamhet. Studien ämnar även till att analysera det eventuella gap som existerar mellan leverantör och köpare. Studien utförs genom att använda en kvalitativ metod. Genom kvalitativa intervjuer med representanter från ett urval av IT-avdelningar från kommuner inom Västra Götalands län och representanter från molntjänstleverantörer, samlas information in som sedan analyseras och används för att utveckla en checklista som kan användas vid upphandling av molntjänster inom kommunal verksamhet. Befintlig bakgrundslitteratur har även beaktats och analyserats under studien. Resultatet visar att samtliga kommuner involverade i studien använder sig av upphandlade molntjänster i någon utsträckning och är dagsläget i behov av de positiva egenskaper som molntjänster bidrar med till verksamheten. Resultatet visar även att det finns ett visst gap mellan leverantör och kommunal verksamhet när det kommer till vad som anses vara tydlig kravställning på interoperabilitet. / Cloud services offer scalable IT resources on demand over the Internet, where the cloud service user only pays for consumption. These resources can vary between everything from processing power to storage (Amazon, 2019). The digitization of society has contributed to an increased demand for innovative solutions. This has resulted in cloud services increasing in popularity in the public sector for example in municipal activities where the trend indicates that demand for cloud services and the use of cloud solutions continue to increase. When public actors choose to implement cloud services, it is important that the information handled by a cloud service maintains a high level of information security (Hellberg, Islam, & Karlsson, 2018). Important aspects that municipal activities should consider are functionality and legal requirements. In addition to these aspects, cloud service customers should also set clear requirements for the technical challenges that exist in order to ensure that the solution provided meets the operational criteria for interoperability and data portability. The purpose of this study is to develop a checklist that can be used in the procurement of cloud services within municipal activities. The study also aims to analyze the possible gap that exists between the supplier and the buyer. The study is performed using a qualitative method. Through qualitative interviews with representatives from a selection of IT departments from municipalities within the county of Västra Götaland, information is collected then analyzed and used to develop a checklist that can be used in procurement of cloud services within municipal activities. Existing background literature has also been considered and analyzed during the study. The result shows that all municipalities involved in the study make use of procured cloud services to some extent and are currently in need of the positive properties that cloud services contribute to the business. The result also shows that there is a certain gap between supplier and municipal activity when it comes to what is considered to be clear requirements regarding interoperability.

雲端運算是近來全世界最熱門的資訊議題，任何設備只要能夠連上網路，就可以享有各種不同的網路服務，這些服務可能建置在不同的機器設備上，甚至可能在相隔遙遠的雲端裡，因此也稱之為雲端服務，在操作過程中，使用者不需要擔心服務安裝在哪裡，亦不用擔心服務如何達成，可想而知網路服務的背後，隱藏著很複雜的技術與架構。 網路服務的開發方式相當地簡單且快速，為系統帶來更大的便利與彈性，不過在管理的部份，卻變得越來越複雜，例如不易瞭解網路的結構與狀態、潛在的無窮迴圈及冗餘的流程問題，甚至是在資源共享的情況下，因等待或其他因素而導致死結的情況產生。這些問題將使得網路服務組合在執行時期，可能發生無法預期的錯誤。情況嚴重時，系統可能會完全鎖死或停止，對公司將造成重大的財務及商譽上的損失。這些流程的問題，需要在網路服務組合執行前先進行驗證，本研究透過流程轉換成派翠網路的分析，以確保流程設計的正確性與穩定性。 因此，本論文運用網路服務標準，將雲端服務轉換成派翠網路模型，再以派翠網路中的針織法為分析基礎，檢驗模型的狀態，避免死結發生，並提供網路特徵報告書，以降低管理的複雜度，進而提升服務的穩定性。 / Cloud computing is regarded as the most popular recent ICT topic. Any equipment which can be connected to Internet can provide its user have the access to the various services, which may be built on different machines, or even may exist in the distant 'clouds' far away. However, in the operating process, the user has no need to worry where the service locates, needless to say how the service operates, which means that a considerably amount of data and techniques hide behind the Web service. Web service is an artifical piece of art, the user and the manager can concatenate several Web services online into a bigger one according to the conditions they need, which is a considerably simple and fast developing method bringing more convenience and flexibility for the system. Nonetheless, the managerial part also becomes more complex in problems like potential infinite loops and abundant procedures, for instance. What is worse is under the circumstance of resource sharing, the deadlocks happen while pending or other factors occur. These issues will lead to severe errors while the Web service compound operates. If the system completely locks and stops, serious financial damage and loss of commercial reputation will be caused to the company. Hence the design of procedures needs to be validated and transformed as Petri Net analysis before the Web service compound operates in order to assure the accuracy and stability of the procedure design. Therefore, this paper uses Web service standards, turning Web services into Petri Net models with knitting technique as analytical base, to validate the accuracy and stability of the model to avoid deadlock to happen in order to enhance the reliability of the service.

Cloud computing has been given a great deal of attention during recent years. Almost all the technology market leaders and leading hosting service providers (like IBM, Microsoft and Verizon) have entered into the Cloud market as Cloud Providers. Cloud computing promises to provide highly available, secure, low cost, agile and highly scalable solution to the consumers. Scania is a global company and one of the world’s leading heavy vehicle manufacturers with 35,000+ employees. All the large organizations such as Scania, aim to constantly update themselves with the latest technology in order to meet their business requirements but, these organizations must always be convinced that there is a strong reason(s) to implement new technology. This research provides the method and criteria in relation to initiating Cloud computing. A number of Scania’s specific business requirements that it is possible to map to the Cloud are addressed in this thesis. The methodology of research is split in two parts. Firstly, the identification of business cases at Scania and their requirements with the Cloud and Secondly, the evaluation and comparison of the functionalities and capabilities of different vendors. The accumulated data is then compared and suitable vendors, according to those business requirements are suggested. This thesis also shares the experience of moving on premise applications to the Cloud. These are Scania specific applications which are currently being hosted in-house. The research also addresses the possibilities of portability between the Cloud providers. Although there is no standardization in relation to Cloud computing, some initiatives such as OpenStack are available and its current position and some application and data migration tools are also discussed. The thesis concludes with a general discussion, recommendations in relation to adapting Cloud computing and selecting the Cloud provider. This recommendation applies to every organization including Scania.

As plataformas de serviços de bibliotecas, em inglês library services plataforms (LSP), são sistemas para gerenciamento unificado de todo o espectro de materiais, impressos, eletrônicos e digitais, que compõem as coleções das bibliotecas atualmente. Utilizados desde 2012, somente por instituições fora do Brasil, estes sistemas são providos mediante serviços em nuvem, no modelo Software-as- a-Service e em arquitetura multi-tenant. Esta nova tecnologia, considerada disruptiva, traz mudanças nos processos de trabalho das equipes das bibliotecas e da área de tecnologia da informação. A adoção de um novo sistema, recente e contemporâneo, requer sólida fundamentação sobre seus benefícios, de modo a justificar, junto aos gestores das organizações, os investimentos necessários. Estudos indicam que o sucesso de um sistema de informação pode ser verificado através da avaliação da satisfação dos usuários desse sistema. Com o objetivo de compreender o fenômeno da adoção das plataformas de serviços de bibliotecas, esta pesquisa explora as percepções avaliativas de seus usuários internos, através de uma abordagem qualitativa e por meio de um estudo de caso. A coleta de dados se apoia na pesquisa documental e na realização de entrevistas com os funcionários da Biblioteca da University of Surrey (Guilford, Inglaterra), usuários internos da plataforma de serviços de bibliotecas Alma O roteiro para condução das entrevistas baseia-se no modelo de antecedentes da formação da satisfação de usuários finais, dos autores Au, Ngai e Cheng (2008), e busca identificar os construtos principais e determinantes da satisfação ou da insatisfação dos funcionários da Biblioteca em relação ao sistema de gerenciamento utilizado. A pesquisa conclui que a qualidade do sistema é o construto de maior satisfação entre os usuários da LSP, enquanto que a qualidade do suporte ao sistema pode ser melhorada. Demonstra que o equilíbrio para o atendimento do desempenho do trabalho é relevante para os usuários, revelando que os esforços são altos, mas os benefícios compensam. As narrativas dos entrevistados evidenciam que a implantação da plataforma de serviços de bibliotecas implica em mudar o modo de fazer habitual, propõe rever e estabelecer novos fluxos de trabalho e cria interfaces entre setores e atividades. Este processo afeta o status quo organizacional e permeia as relações interpessoais no trabalho - o que requer suporte de uma forte estratégia motivacional. / Library services platforms (LSP) are the new genre of library management systems. They manage all type of materials that belong to the libraries collections today - printed, electronic and digital. These systems are being used by libraries all over the world since 2012, but not yet in Brazil. The new systems are provided through a Software-as-a-Service (SaaS) model and multi-tenant architecture. This new disruptive technology changes the current workflow processes involving the library and the information technology areas. The adoption of a modern, new and recent system requires a clear vision about its benefits to justify the decision and the necessary financial support to the institution managers. Many earlier studies have found relations between the information system success and the end users satisfaction. The aim of this research is to study the adoption of a library services platform phenomenon based on the perceptions and evaluations of its end users, through a qualitative approach and applying a case study method. The data collection was performed through documental research and interviews with the staff of the University of Surrey Library (Guilford, England), which uses the Alma library services platform The interview script followed the model of antecendents of end users satisfaction formation proposed by Au, Ngai e Cheng (2008) and seeks to confirm the main and determinant constructs of the library staff users´ satisfaction or dissatisfaction regarding the management system used. The research concludes that the system quality is the highest satisfaction construct among LSP users, while system support quality can be improved. It demonstrates that equitable work performance fulfillment is relevant for the users, and despite their inputs and efforts, the benefits are considered valuable. The respondents´ narratives highlight that the library services platform implementation changes the usual way of doing things, establishes new and improved workflows and creates interfaces between departments and activities. This processs affects the organizational status quo and permeates interpersonal relations in the workplace, which requires a strong motivational strategy.

As plataformas de serviços de bibliotecas, em inglês library services plataforms (LSP), são sistemas para gerenciamento unificado de todo o espectro de materiais, impressos, eletrônicos e digitais, que compõem as coleções das bibliotecas atualmente. Utilizados desde 2012, somente por instituições fora do Brasil, estes sistemas são providos mediante serviços em nuvem, no modelo Software-as- a-Service e em arquitetura multi-tenant. Esta nova tecnologia, considerada disruptiva, traz mudanças nos processos de trabalho das equipes das bibliotecas e da área de tecnologia da informação. A adoção de um novo sistema, recente e contemporâneo, requer sólida fundamentação sobre seus benefícios, de modo a justificar, junto aos gestores das organizações, os investimentos necessários. Estudos indicam que o sucesso de um sistema de informação pode ser verificado através da avaliação da satisfação dos usuários desse sistema. Com o objetivo de compreender o fenômeno da adoção das plataformas de serviços de bibliotecas, esta pesquisa explora as percepções avaliativas de seus usuários internos, através de uma abordagem qualitativa e por meio de um estudo de caso. A coleta de dados se apoia na pesquisa documental e na realização de entrevistas com os funcionários da Biblioteca da University of Surrey (Guilford, Inglaterra), usuários internos da plataforma de serviços de bibliotecas Alma O roteiro para condução das entrevistas baseia-se no modelo de antecedentes da formação da satisfação de usuários finais, dos autores Au, Ngai e Cheng (2008), e busca identificar os construtos principais e determinantes da satisfação ou da insatisfação dos funcionários da Biblioteca em relação ao sistema de gerenciamento utilizado. A pesquisa conclui que a qualidade do sistema é o construto de maior satisfação entre os usuários da LSP, enquanto que a qualidade do suporte ao sistema pode ser melhorada. Demonstra que o equilíbrio para o atendimento do desempenho do trabalho é relevante para os usuários, revelando que os esforços são altos, mas os benefícios compensam. As narrativas dos entrevistados evidenciam que a implantação da plataforma de serviços de bibliotecas implica em mudar o modo de fazer habitual, propõe rever e estabelecer novos fluxos de trabalho e cria interfaces entre setores e atividades. Este processo afeta o status quo organizacional e permeia as relações interpessoais no trabalho - o que requer suporte de uma forte estratégia motivacional. / Library services platforms (LSP) are the new genre of library management systems. They manage all type of materials that belong to the libraries collections today - printed, electronic and digital. These systems are being used by libraries all over the world since 2012, but not yet in Brazil. The new systems are provided through a Software-as-a-Service (SaaS) model and multi-tenant architecture. This new disruptive technology changes the current workflow processes involving the library and the information technology areas. The adoption of a modern, new and recent system requires a clear vision about its benefits to justify the decision and the necessary financial support to the institution managers. Many earlier studies have found relations between the information system success and the end users satisfaction. The aim of this research is to study the adoption of a library services platform phenomenon based on the perceptions and evaluations of its end users, through a qualitative approach and applying a case study method. The data collection was performed through documental research and interviews with the staff of the University of Surrey Library (Guilford, England), which uses the Alma library services platform The interview script followed the model of antecendents of end users satisfaction formation proposed by Au, Ngai e Cheng (2008) and seeks to confirm the main and determinant constructs of the library staff users´ satisfaction or dissatisfaction regarding the management system used. The research concludes that the system quality is the highest satisfaction construct among LSP users, while system support quality can be improved. It demonstrates that equitable work performance fulfillment is relevant for the users, and despite their inputs and efforts, the benefits are considered valuable. The respondents´ narratives highlight that the library services platform implementation changes the usual way of doing things, establishes new and improved workflows and creates interfaces between departments and activities. This processs affects the organizational status quo and permeates interpersonal relations in the workplace, which requires a strong motivational strategy.

The usage of cloud computing in order to move away from local servers and infrastructure have grown enormously the last decade. The ability to quickly scale capacity of servers and their resources at once when needed is something that can both be a price saver for companies and help them deliver high end products that will function correctly at all times even under heavy load to their customers. To meet todays challenges, one of the strategic directions of Attentec, a software company located in Linköping, is to examine the world of cloud computing in order to deliver robust and scalable applications to their customers. This thesis investigates the usage of cloud services in order to deploy scalable applications which can adapt to usage peaks within minutes.

Vi lever i ett informationssamhälle. Idag hittar vi fakta om vad som helst, var vi än är, genom de gigantiska och otroliga resurser som nås via ICT idag. Med ökad teknisk kapacitet har informationsinsamlingen ökat drastiskt i mängd. Hur vi lagrar data är dock mindre diskuterat. Det nya skifte som kommit fram i datalagring är en flytt från lokalt förvaltade servrar till lagring i molnet. Molntjänster är ett idag allmänt känt begrepp inom IT-branschen, men för att få så mycket uppmärksamhet är termen väldigt vag. Uppsatsen syftar till att reflektera kring molnets innebörd samt utreda om molnet lämpas för datalagring. Studien fastställer vilken affärsnytta en organisation kan utvinna av datalagring i molnet samt om de problem som finns det datalagring idag kan lösas genom att flytta lagringen till molnet. De problem som kommer med den ökade datamängden i informationssamhället samt de lagringstekniker i form av servrar som används idag, presenteras. Teoretiska definitioner av molnet framställs samt hur dessa definitioner skiljer sig från användares synsätt. Resultatet som presenteras ger en definition av hur molntjänster kan användas av organisationer för att lagra data samt vad organisationer kan utvinna av detta. / Today’s information society brings big changes in how we gather information. During the last couple of years the amount of information we store has increased substantially. Techniques for gathering information develops fast, but the way we store information stays the same. This study looks in to cloud computing and if storing data in the cloud is a good alternative to local storage. The definition of cloud computing is vague, and this study attempts to give an account for what cloud computing is through theories and user definitions. Problems with the amount of increased data, and server techniques we use today are presented. The study confirms business advantages with storing data in the cloud and give clearance to that the cloud is working alternative to local storage.

As plataformas de serviços de bibliotecas, em inglês library services plataforms (LSP), são sistemas para gerenciamento unificado de todo o espectro de materiais, impressos, eletrônicos e digitais, que compõem as coleções das bibliotecas atualmente. Utilizados desde 2012, somente por instituições fora do Brasil, estes sistemas são providos mediante serviços em nuvem, no modelo Software-as- a-Service e em arquitetura multi-tenant. Esta nova tecnologia, considerada disruptiva, traz mudanças nos processos de trabalho das equipes das bibliotecas e da área de tecnologia da informação. A adoção de um novo sistema, recente e contemporâneo, requer sólida fundamentação sobre seus benefícios, de modo a justificar, junto aos gestores das organizações, os investimentos necessários. Estudos indicam que o sucesso de um sistema de informação pode ser verificado através da avaliação da satisfação dos usuários desse sistema. Com o objetivo de compreender o fenômeno da adoção das plataformas de serviços de bibliotecas, esta pesquisa explora as percepções avaliativas de seus usuários internos, através de uma abordagem qualitativa e por meio de um estudo de caso. A coleta de dados se apoia na pesquisa documental e na realização de entrevistas com os funcionários da Biblioteca da University of Surrey (Guilford, Inglaterra), usuários internos da plataforma de serviços de bibliotecas Alma O roteiro para condução das entrevistas baseia-se no modelo de antecedentes da formação da satisfação de usuários finais, dos autores Au, Ngai e Cheng (2008), e busca identificar os construtos principais e determinantes da satisfação ou da insatisfação dos funcionários da Biblioteca em relação ao sistema de gerenciamento utilizado. A pesquisa conclui que a qualidade do sistema é o construto de maior satisfação entre os usuários da LSP, enquanto que a qualidade do suporte ao sistema pode ser melhorada. Demonstra que o equilíbrio para o atendimento do desempenho do trabalho é relevante para os usuários, revelando que os esforços são altos, mas os benefícios compensam. As narrativas dos entrevistados evidenciam que a implantação da plataforma de serviços de bibliotecas implica em mudar o modo de fazer habitual, propõe rever e estabelecer novos fluxos de trabalho e cria interfaces entre setores e atividades. Este processo afeta o status quo organizacional e permeia as relações interpessoais no trabalho - o que requer suporte de uma forte estratégia motivacional. / Library services platforms (LSP) are the new genre of library management systems. They manage all type of materials that belong to the libraries collections today - printed, electronic and digital. These systems are being used by libraries all over the world since 2012, but not yet in Brazil. The new systems are provided through a Software-as-a-Service (SaaS) model and multi-tenant architecture. This new disruptive technology changes the current workflow processes involving the library and the information technology areas. The adoption of a modern, new and recent system requires a clear vision about its benefits to justify the decision and the necessary financial support to the institution managers. Many earlier studies have found relations between the information system success and the end users satisfaction. The aim of this research is to study the adoption of a library services platform phenomenon based on the perceptions and evaluations of its end users, through a qualitative approach and applying a case study method. The data collection was performed through documental research and interviews with the staff of the University of Surrey Library (Guilford, England), which uses the Alma library services platform The interview script followed the model of antecendents of end users satisfaction formation proposed by Au, Ngai e Cheng (2008) and seeks to confirm the main and determinant constructs of the library staff users´ satisfaction or dissatisfaction regarding the management system used. The research concludes that the system quality is the highest satisfaction construct among LSP users, while system support quality can be improved. It demonstrates that equitable work performance fulfillment is relevant for the users, and despite their inputs and efforts, the benefits are considered valuable. The respondents´ narratives highlight that the library services platform implementation changes the usual way of doing things, establishes new and improved workflows and creates interfaces between departments and activities. This processs affects the organizational status quo and permeates interpersonal relations in the workplace, which requires a strong motivational strategy.

Preserving the performance of cloud services according to service level agreements (SLAs) is one of the most important challenges in cloud infrastructure. Since the workload is always changing incrementally or decremental, managing the cloud resources efficiently is considered an important challenge to satisfy non-functional requirements like high availability and cost. Although many common approaches like predictive autoscaling could solve this problem, it is still not so efficient because of its constraints like requiring a workload pattern as training data. Reinforcement machine learning (RL) can be considered a significant solution for this problem. Even though reinforcement learning needs some time to be stable and needs many trials to decide the value of factors like discount rate, this approach can adapt with the dynamic workload. In this  thesis, through a controlled experiment research method, we show how a model-free reinforcement algorithm like Q-learning can adapt to the dynamic workload by applying horizontal autoscaling to keep the performance of cloud services at the required level. Furthermore, the Amazon web services (AWS) platform is used to demonstrate the efficiency of the Q-learning algorithm in dealing with dynamic workload and achieving high availability.