The aim of the work reported in this thesis is to establish a generic approach for the study of the propagation of higher-order modes in ducts of circular cross section when a simple aperture device is installed in the duct. Additionally to describe the effects of the simple aperture device on the whole in duct acoustic field, especially in the frequency range after the first higher-order mode cuts on. The approach, which is based on approximating each higher-order mode as an uncoupled mode, requires an accurate and effective decomposition of the in duct field in the higher frequency range. In the theoretical work for the propagation of the higher-order modes in circular ducts, one established model to describe the open end of the duct is considered. Another model to describe the sound source (both plane wave source and point source) and the boundaries between the aperture device and the main duct is proposed. Combining the two models together, a revised model to describe the whole acoustic system is obtained and used to carry out the in duct field decomposition in the higher frequency range. From this the amplitudes of various higher-order modes are obtained. Experimental investigations have also been carried out to determine the applicability of this model. The experimental work can be divided into two groups: reference measurements for the inputs to the models and direct measurements of the sound fields. The reference measurements are used to obtain the strength of the sound source. The direct measurements are used to compare with the results obtained from the theoretical calculations. Through the comparison, the errors and the applicability of the theoretical model are established. It is shown that this approach to the problem may be used in the normalized wave number region up to k * R -< 7 , which is nearly four times the plane wave region and includes sixteen propagating higher-order modes. By determining the amplitudes of the higher-order modes, the whole in-duct acoustic field is fully decomposed into individual model contributions and can be reconstructed in detail. In order to get a complete and coordinate-independent description of the effects of installing different simple aperture devices, the power radiated out of the open end of - i - the duct is calculated in the fonn of different single modes. Additionally the insertion losses for different aperture device situations are also obtained. Then through the comparison of the powers and the insertion losses, it is possible to find an effective and direct way to express the effects of installing different simple aperture devices in a duct.

Σε αυτή τη Διπλωματική εργασία μελετάται η ταλαντωτική συμπεριφορά μιας κυκλικής πλάκας γραφενίου προκειμένου να διαπιστωθεί αν μπορεί να λειτουργήσει σαν νανομηχανική συσκευή ανίχνευσης μάζας. Για το λόγο αυτό δημιουργήθηκε και χρησιμοποιήθηκε ένα μοντέλο πεπερασμένων στοιχείων. Σε αυτό το μοντέλο οι αλληλεπιδράσεις μεταξύ των ατόμων και οι σχετικές κινήσεις αυτών προσομοιώθηκαν με κατάλληλα ελατήρια των οποίων η δυσκαμψία έχει υπολογιστεί χρησιμοποιώντας την ενέργεια δεσμού από τη θεωρία των μορίων. Ακόμη, τα άτομα του άνθρακα προσομοιώνονται με μάζες στη θέση των ατόμων άνθρακα. Το αναπτυχθέν μοντέλο αναπαριστά το δίσκο του γραφενίου σαν ορθότροπο υλικό. Προκείμενου να αποκτηθεί μια καλή εικόνα της συμπεριφοράς του κυκλικού γραφενίου γίνεται αρχικά διερεύνηση της ελεύθερης ταλάντωσης για διάφορες διαμέτρους αυτού. Επιπλέον, εξετάζεται η ταλαντωτική συμπεριφορά του γραφενίου με την προσκόλληση μάζας διαφόρων μεγεθών και σε διάφορες θέσεις πάνω στο γραφένιο κατά μήκος της ακτίνας του. Η επεξεργασία των μοντέλων έχει ως αποτέλεσμα τις φυσικές συχνότητες ταλάντωσης του γραφενίου και τις αντίστοιχες ιδιομορφές των φύλλων γραφενίου με ή χωρίς την προσκολλημένη μάζα παρέχοντας τα ταλαντωτικά τους χαρακτηριστικά. Επομένως, έχοντας δημιουργήσει μοντέλα για διάφορες διαμέτρους και μάζες μπορεί να εξεταστεί και να αποκτηθεί μια πλήρης εικόνα για την ενδεχόμενη ταλαντωτική συμπεριφορά του κυκλικού μονοστρωματικού δίσκου γραφενίου σαν αισθητήριο μάζας. / In this Diploma thesis is studied the vibrational behavior of a circular graphene sheet so as to investigate if this can operate as a nanomechanical system of mass sensing. For this purpose a finite elements’ model was created and being used. In this model the interatomic interactions and their relative positions are simulated by equivalent spring elements whose stiffness derived by corresponding potential energies provided by molecular theory and expressing the resistance in relative movements between carbon atoms under deformation. Moreover, the inertial effects of the system are simulated by using appropriate lumped masses in atomic positions. The model created represents the graphene plate as an orthotropic material. In order to obtain a full view of the behavior of circular graphene, firstly is been done investigation of its free vibration for different diameters of the plate. After that, is studied the Vibrational behavior with a mass lying on it. The solution gives the natural frequencies and corresponding mode shapes of vibration of individual graphene sheets and graphene-attached mass systems providing their vibrational characteristics. Subsequently, assuming the geometric characteristics of graphene as well as the weight and position of the attached mass as the global design parameters, a parametric study on mass sensing characteristics is presented in order to examine the potential behavior of a circular graphene monolayer as mass sensor.

在這篇論文中，我們利用分離－收縮法(splitting-contraction algorithm)獲得一個擁有完全C邊以及循環D邊特性的圖之著色多項式。 假如一個混合超圖在點集合上有主要的循環， 使得所有的C邊和D邊包含一個主循環(host cycle)的連接子圖， 則稱此圖為循環的(circular)。 對於每個l≧2， 所有連續l個點會形成一個D邊時， 我們把D記作D_l。 如此一來， 超圖(X,Φ,D_2)就是圖論中n個點的普通循環。 我們先觀察擁有完全C邊和循環D邊的超圖， 利用分離－收縮法的第一步， 找到遞迴關係式並且解它。 然後我們就推廣到一般完全C邊及循環D邊的超圖。 / In this thesis, we obtain the chromatic polynomial of a mixed hypergraph with complete C-edges and circular D-edges by using splitting-contraction algorithm. A mixed hypergraph H=(X,C,D) is called circular if there exists a host cycle on the vertex set X such that every C-edge and every D-edge induces a connected subgraph of the host cycle. For each l≧2, we denote D by D_l if and only if every l consecutive vertices of X form a D-edge. Thus the mixed hypergraph (X,Φ,D_2) is a simple classical cycle on n vertices. We observe first a mixed hypergraph with complete C-edges and D_2. By the first step of the splitting-contraction algorithm, we can find out the recurrence relation and solve it. Then we generalize the mixed hypergraph with complete C-edges and circular D-edges.

中國政府自2005年開始進行第一批循環經濟試點計畫。循環經濟強調資源減量化、再利用及再循環的原則，促成企業降低成本、減少污染排放並提高資源利用率。而目前探討循環經濟對效率影響之研究甚少，且研究大多著重於區域層級。因此本研究針對2004年至2007年的循環經濟試點公司，利用資料包絡分析法求出公司技術效率值並分析其長期趨勢，以探討公司採行循環經濟後是否能實質增加其營運效率。 研究結果發現，實施循環經濟後，循環經濟試點單位之技術效率與純技術效率呈現上升的趨勢，且其效率值亦顯著的高於非試點公司，顯示實施循環經濟確實有助於企業技術效率之提升。 / Chinese government has started to implement the first circular economy pilots program since 2005. Circular economy emphasizes the principle of reducing, reusing and recycling resource to promote enterprises to reduce cost, cut down pollution and enhance the use of resource. This research tried to apply Data Envelopment Analysis (DEA) to examine whether the companies improve their operating efficiency after implementing circular economy program. The samples include18 pilot companies and 18 matching samples 4 years data from 2004 to 2007. The research major finding reveals that after implementing the circular economy the pilot companies have significantly improved their technical efficiency and pure technical efficiency than those of non-pilots companies. The result suggests that pilot companies indeed help the companies to gain more efficiency after implement of circular economy.

In teleconferencing the audio quality is key to conducting successful meetings. The conference room setting imposes various challenges on the speech signal processing, such as noise and interfering signals, reverberation, or participants positioned far from the telephone unit. This work aims at improving the received speech signal of a conference telephone by implementing sound source localization and beamforming. The implemented microphone array signal processing techniques are compared to the performance of an existing multi-microphone solution and evaluated under various conditions using a planar uniform circular array. Recordings of test-sequences for the evaluation were performed using a custom-built array mockup. The implemented algorithms did not show good enough performance to motivate the increased computational complexity compared to the existing solution. Moreover, an increase in number of microphones used was concluded to have little or no effect on the performance of the methods. The type of microphone used was, however, concluded to have impact on the performance and a subjective listening evaluation indicated a preference for omnidirectional microphones which is recommended to investigate further. / God ljudkvalitet är en grundsten för lyckade telefonmöten. Miljön i ett konferens-rum medför ett flertal olika utmaningar för behandlingen av mikrofonsignalerna: det kan t.ex. vara brus och störningar, eller att den som talar befinner sig långt från telefonen. Målet med detta arbete är att förbättra den talsignal som tas upp av en konferenstelefon genom att implementera lösningar för lokalisering av talaren och riktad ljudupptagning med hjälp av ett flertal mikrofoner. De implementerade metoderna jämförs med en befintlig lösning och utvärderas under olika brusscenarion för en likformig cirkulär mikrofonkonstellation. För utvärderingen användes testsignaler som spelades in med en specialbyggd enhet. De implementerade algoritmerna kunde inte uppvisa en tillräcklig förbättring i jämförelse med den befintliga lösningen för att motivera den ökade beräkningskomplexitet de skulle medföra. Dessutom konstaterades att en fördubbling av antalet mikrofoner gav liten eller ingen förbättring på metoderna. Vilken typ av mikrofon som användes konstaterades däremot påverka resultatet och en subjektiv utvärdering indikerade en preferens för de rundupptagande mikrofonerna, en skillnad som föreslås undersökas vidare.

More than 1.2 million students have left China to study abroad during the past three decades of economic reform in China. In 2007 alone, China sent around 144,000 students abroad, 167 times of the number of students in 1978. This large scale of student migration has often raised debate on brain drain , because many of these student migrants do not return to China upon graduation. However, there has been a reverse trend in the past decade as China witnessed a growing wave of return migration. More and more Chinese students are coming back to China after their studies and work abroad due to the strong economic situation and promising career opportunities at home. These returnees are given the nick-name Haigui or, in English, sea-turtles. This doctoral research is therefore an academic inquiry to this emerging social phenomenon. While international migration is mainly researched on the national level, this innovative doctoral research seeks to understand the relationship between migration and global city formation. To do so, it analyses inter-city migration flow by applying a relational case study of circular student migration between Shanghai and Paris and examines the rationale behind return migration and the role of management/business student returnees from French business schools on Shanghai s pathway to become China s premier global city. This research reveals that global cities have become the strategic points for Chinese talents (students and skilled professionals) acting the role as sending, transiting and receiving sites, which are interconnected in the dynamic process of knowledge accumulation, contact making and network creation. Chinese student returnees contribute to the development of Shanghai by actively engaging in transnational activities including developing and maintaining cross-border organisation/corporate ties and personal networks, knowledge transfer, acting as global-local business and cultural interface, as well as enriching cosmopolitan and multicultural business and cultural spaces in Shanghai.

Författare: Susanne Nilsson och Tova Swerlander Handledare: Christine Tidåsen och Charlotte Hahn Examinator: Christine Tidåsen Titel: Vägen mot hållbara val En studie om hållbar konsumtion och cirkulär ekonomi inom möbler och inredning Kurs: Kandidatuppsats, 15 hp. Företagsekonomi, Inrednings- och butikskommunikation, Ekonomihögskolan, Linnéuniversitetet, VT17. Problemdiskussion: Studien ämnar till att skapa förståelse kring möjligheter för en mer hållbar konsumtion inom möbler och inredning eftersom att denna kategori är en av de mest ökande. Hållbar konsumtion är en del av den cirkulära ekonomiska affärsmodellen. Syfte: Studien syftar till att skapa förståelse för vad som möjliggör en mer hållbar konsumtion av möbler och inredning. Metod: Studien har grundats på en kvalitativ forskningsmetod och forskningsansatsen har varit abduktiv. För att skapa förståelse för ämnet hållbar konsumtion och cirkulär ekonomi har vi genomfört semistrukturerade intervjuer med konsumenter, experter och företag. Slutsats: Studien tyder på att hållbar konsumtion inom möbler och inredning kan möjliggöras på flera sätt och det är många faktorer som påverkar. En omställning till cirkulär ekonomi är nödvändig för att en hållbar konsumtion ska vara möjlig fullt ut. / Authors: Susanne Nilsson och Tova Swerlander Supervisor: Christine Tidåsen och Charlotte Hahn Examiner: Christine Tidåsen Title: The way to sustainable choices A study about sustainable consumption and circular economy in furniture and interior design Subject: Bachelor thesis, 15 credits. Business Administration, Interior Design and Visual Merchandising, School of Business and Economics, Linnaeus University, Spring 17 Research: The authors wish to create an understanding of the opportunities for more sustainable consumption of furniture and interior, as this category is one of the most growing. Sustainable consumption is part of the circular economic business model. Purpose: The purpose is to create an understanding of what can contribute to a more sustainable consumption of furniture and interior. Method: This study is based on a qualitative research method and the research process has been abductive. In order to create an understanding of the topic, semi-structured interviews have been made with consumers, experts and a person from the furniture business. Conclusion: This study indicates that sustainable consumption of furniture and interior can be made in several ways and many factors affects. A switch to circular economy is necessary for sustainable consumption to be fully possible.

Geospatial data almost always contains some amount of uncertainty due to inaccuracies in its acquisition and transformation. While the data is commonly visualized (e.g. on digital maps), there are unanswered needs for visualizing uncertainty along with it. Most research on effectively doing this addresses uncertainty in data values at geospatial positions, e.g. water depth, human population, or land-cover classification. Uncertainty in the data’s geospatial positions themselves (positional uncertainty) has not been previously focused on in this regard. In this thesis, techniques were created for visualizing positional uncertainty using World Vector Shoreline as an example dataset. The techniques consist of a shoreline buffer zone to which visual effects such as gradients, transparency, and randomized dots were applied. They are viewed interactively via Web Map Service (WMS). In clutter testing with human subjects, a transparency-gradient technique performed the best, followed by a solid-fill technique, with a dots-density-gradient technique performing worst.

Informationsteknologi, IT, och hållbarhetsarbete har blivit två strategiska frågor i nästintill alla företag. Företag måste implementera IT för att optimera nuvarande verksamheter och transformeras till IT-drivna affärsmodeller som kräver hög kompetens och strategiskt tänkande vilket många små- och medelstora företag, SMF, saknar. Att köpa rekonditionerad IT-hårdvara är ett alternativ till att agera hållbart. Däremot erbjuder de företag som levererar rekonditionerad IT sällan mycket mer än just hårdvara eftersom de också ofta saknar de resurser som krävs för att tillhandahålla ytterligare tjänster inom IT. IT-tjänster är ofta avgörande om SMF ska bli kunder eller inte eftersom att köpa all IT från en leverantör minimerar administrationskostnader samtidigt som det skapar djupare relationer mellan kunden och leverantören. De bristande interna resurserna bland SMF har lett till att de frigör delar eller hela verksamheter till externa leverantörer. Frigörandet är däremot inte riskfritt för SMF. Att överlämna delar av verksamheten till externa leverantörer kräver nära relationer med leverantörer vilket gör kommunikationen mellan dem avgörande. Ett sätt för leverantörer att skapa relationer med kunder är genom att utveckla tjänstefiering, det vill säga gå från varucentrerat till tjänstecentrerat erbjudande. För att utveckla tjänstefiering, trots avsaknaden av interna resurser, måste leverantörer samproducera erbjudanden. Genom att skapa ett interaktivt samarbete i nätverk där aktörer tillsammans tillhandahåller erbjudanden har lett till nya värdeskapande system kallat värdekonstellationer. Leverantörer och kunder är nu tillsammans med och skapar värde och kunden ses inte längre som konsument utan snarare medproducent då de är med och deltar i produktionen. Aktörernas roll har således blivit vidgade. De bristande resurserna är inte längre ett hinder för att utveckla nya erbjudanden eftersom de i konstellationen bidrar med resurser samtidigt som de bygger relationer med varandra. / Information technology, IT, and sustainability work have become strategic questions in almost any business. Not only do firms have to implement IT to optimize current operations, they must transform into new business models which requires high level of competence and strategic thinking which especially small and medium-sized enterprises, SME, tend to lack. Buying refurbished IT-hardware is an option for SME to act sustainable. However, suppliers of those goods seldom offer much more as they too tend to lack the resources needed to provide IT services. IT services are usually critical whether SME will become customers or not since buying IT from one supplier minimizes administration costs as well as it creates deeper relationships. Lack of internal resources has led to SMF outsource parts or whole operations more frequently to external suppliers. But the outsourcing does not come harmless. Leaving an operation to an external supplier requires close relationship with the supplier to maintain quality, making the communication vital. A way for a supplier to facilitate relationships is to develop servitization, i.e go from product- to service-centric offers. To develop servitization regardless the scarce resources suppliers have to co-produce offers. Creating an interactive strategy in networks consisting of actors that co-produce offers creates new value creating systems- value constellations. Suppliers and customers are now part of the value creation as they both participate in the production. Their roles have been broadened and the scarce resources as a barrier has now been eliminated as they now share competences while their relationships are being flourished.

Circular economy has emerged as a new economic paradigm to solve problems of natural resource scarcity and environmental pollution by using resources more efficiently and designing products to minimize waste. This study examines the potential of circular economy to enable the achievement of sustainable development and the Sustainable Development Goals in Europe. This thesis, through a qualitative content analysis of four overarching European reports related to circular economy strategies, uses a social-ecological systems perspective to: (a) analyze how the three aspects of sustainable development are addressed in the reports and (b) pointing out at missing elements in the European circular economy project that could hinder the realization of the Sustainable Development Goals. Circular economy is a good start to change habits in terms of recycling, reusing and repairing but it also raises awareness about the link between our level of consumption and production and its impact on the environment. However, the results of this study show that the link between Sustainable Development Goals and circular economy is weak and that the economic aspects are highlighted in all the reports to the detriment of environmental and social aspects. As a consequence, the current application of circular economy in Europe does not provide systemic and structural changes, fails to address the root of the problem and reflects a weak vision of sustainability.