Ultra-wideband (UWB) is an appealing transmission technology for short-range, bandwidth demanded wireless communications. With the data rate of several hundred megabits per second, UWB demonstrates great potential in supporting multimedia streams such as high-definition television (HDTV), voice over Internet Protocol (VoIP), and console gaming in office or home networks, known as the wireless personal area network (WPAN). While vast research effort has been made on the physical layer issues of UWB, the corresponding medium access control (MAC) protocols that exploit UWB technology have not been well developed. Given an extremely wide bandwidth of UWB, a fundamental problem on how to manage multiple users to efficiently utilize the bandwidth is a MAC design issue. Without explicitly considering the physical properties of UWB, existing MAC protocols are not optimized for UWB-based networks. In addition, the limited processing capability of UWB devices poses challenges to the design of low-complexity MAC protocols. In this thesis, we comprehensively investigate the MAC protocols for UWB networks. The objective is to link the physical characteristics of UWB with the MAC protocols to fully exploit its advantage. We consider two themes: centralized and distributed UWB networks. For centralized networks, the most critical issue surrounding the MAC protocol is the resource allocation with fairness and quality of service (QoS) provisioning. We address this issue by breaking down into two scenarios: homogeneous and heterogeneous network configurations. In the homogeneous case, users have the same bandwidth requirement, and the objective of resource allocation is to maximize the network throughput. In the heterogeneous case, users have different bandwidth requirements, and the objective of resource allocation is to provide differentiated services. For both design objectives, the optimal scheduling problem is NP-hard. Our contributions lie in the development of low-complexity scheduling algorithms that fully exploit the characteristics of UWB. For distributed networks, the MAC becomes node-based problems, rather than link-based problems as in centralized networks. Each node either contends for channel access or reserves transmission opportunity through negotiation. We investigate two representative protocols that have been adopted in the WiMedia specification for future UWB-based WPANs. One is a contention-based protocol called prioritized channel access (PCA), which employs the same mechanisms as the enhanced distributed channel access (EDCA) in IEEE 802.11e for providing differentiated services. The other is a reservation-based protocol called distributed reservation protocol (DRP), which allows time slots to be reserved in a distributed manner. Our goal is to identify the capabilities of these two protocols in supporting multimedia applications for UWB networks. To achieve this, we develop analytical models and conduct detailed analysis for respective protocols. The proposed analytical models have several merits. They are accurate and provide close-form expressions with low computational effort. Through a cross-layer approach, our analytical models can capture the near-realistic protocol behaviors, thus useful insights into the protocol can be obtained to improve or fine-tune the protocol operations. The proposed models can also be readily extended to incorporate more sophisticated considerations, which should benefit future UWB network design.

Interleukin-3 is a cytokine, which acts on many target cells within the haemopoietic system, often in synergy with the other cytokines. Streptomyces lividans NCIMB 11416/IL3 p002 secreting human interleukin-3 was used as the host organism in this study of improving target protein production. Streptomyces also produces several proteases including extracellular endoprotease that truncate the N-terminus of the recombinant protein. Federal guidelines and regulations banning animal-derived medium components necessitate the refinement or redevelopment of industrial medium formulations. The development of a defined medium without animal products is most desirable for the production of pure and safe biological products. The objective of the proposed research was the development and application of engineering methodology for the development of a defined medium and the analysis and optimization of a bacterial bioprocess for recombinant protein production. The underlying hypothesis is that a significant improvement of target protein productivity is achievable by using appropriate optimization techniques. During the first phase of this study the task was to develop a systematic procedure for the design and optimization of a chemically defined medium. The study aimed at replacing casein peptone in conventional medium for S. lividans with essential amino acids and determining the optimum proportion of the amino acids. To accomplish this, starvation trials with growth limiting amino acids were performed to establish the baseline for the nutritional requirement. The starvation trials revealed that essential amino acids for growth and product formation are amongst the following eight amino acids: Arg, Asn, Asp, Glu, Leu, Met, Phe, and Thr. Following these preliminary experiments, a statistically based experimental method called mixture experiments along with distance-based multivariate analysis revealed that Asp, Leu, Met, and Phe were the essential amino acids. Then, another mixture experiment design known as simplex lattice design was performed and artificial neural networks were employed to obtain the optimum proportions of the essential amino acids. The optimal medium was found to be composed of 56% Asp, 5% Met, and 39% Phe. It was found in previous studies that in complex media, several types of protease are produced during fermentation. Using the defined medium no proteolytic activity was detected in the fermentation broth. The second optimization method was based on metabolic flux analysis. A comprehensive metabolic network was developed for S. lividans. The metabolic network included carbohyderate and amino acid metabolism in both anabolic and catabolic reactions. According to the experimental results, the time course of the fermentation was divided into two phases, Phase E1 and Phase E2. In the first phase amino acids were used as a nitrogen source and in the second phase ammonia was the nitrogen source for growth and product formation. The metabolic network was used to form a set of linear algebraic equations based on the stoichiometry of the reactions by assuming pseudo-steady state for intracellular metabolites. The metabolic flux model consisted of 62 intracellular metabolites and 91 biochemical reactions. Two different objective functions were considered for optimization: maximizing the specific growth rate and minimizing the redox equivalent. A linear programming approach was used for optimizing the objective functions. The proposed model was able to predict the specific growth rate very accurately with a maximum error of 10%. The oxygen uptake rate and carbon dioxide evolution rate were evaluated with maximum error of 27% and 35%, respectively. Sensitivity analysis revealed that amino acid uptake was the growth limiting flux during the Phase E1 of the fermentation. During Phase E2 the uptake rate of ammonia had a significant effect on the specific growth rate. Sensitivity analysis of the specific growth rate and redox potential with respect to the biomass components showed that any additional supply of biomass building blocks (amino acids, nucleotides) would not significantly affect the specific growth rate and redox potential production as well as the calculated flux pattern.

The delay tolerant networks (DTNs) is characterized by frequent disconnections and long delays of links among devices due to mobility, sparse deployment of devices, attacks, and noise, etc. Considerable research efforts have been devoted recently to DTNs enabling communications between network entities with intermittent connectivity. Unfortunately, mobile devices have limited energy capacity, and the fundamental problem is that traditional power-saving mechanisms are designed assuming well connected networks. Due to much larger inter-contact durations than contact durations, devices spend most of their life time in the neighbor discovery, and centralized power-saving strategies are difficult. Consequently, mobile devices consume a significant amount of energy in the neighbor discovery, rather than in infrequent data transfers. Therefore, distributed energy efficient neighbor discovery protocols for DTNs are essential to minimize the degradation of network connectivity and maximize the benefits from mobility. In this thesis, we develop sleep scheduling protocols in the medium access control (MAC) layer that are adaptive and distributed under different clock synchronization conditions: synchronous, asynchronous, and semi-asynchronous. In addition, we propose a distributed clock synchronization protocol to mitigate the clock synchronization problem in DTNs. Our research accomplishments are briefly outlined as follows: Firstly, we design an adaptive exponential beacon (AEB) protocol. By exploiting the trend of contact availability, beacon periods are independently adjusted by each device and optimized using the distribution of contact durations. The AEB protocol significantly reduces energy consumption while maintaining comparable packet delivery delay and delivery ratio. Secondly, we design two asynchronous clock based sleep scheduling (ACDS) protocols. Based on the fact that global clock synchronization is difficult to achieve in general, predetermined patterns of sleep schedules are constructed using hierarchical arrangements of cyclic difference sets such that devices independently selecting different duty cycle lengths are still guaranteed to have overlapping awake intervals with other devices within the communication range. Thirdly, we design a distributed semi-asynchronous sleep scheduling (DSA) protocol. Although the synchronization error is unavoidable, some level of clock accuracy may be possible for many practical scenarios. The sleep schedules are constructed to guarantee contacts among devices having loosely synchronized clocks, and parameters are optimized using the distribution of synchronization error. We also define conditions for which the proposed semi-asynchronous protocol outperforms existing asynchronous sleep scheduling protocols. Lastly, we design a distributed clock synchronization (DCS) protocol. The proposed protocol considers asynchronous and long delayed connections when exchanging relative clock information among nodes. As a result, smaller synchronization error achieved by the proposed protocol allows more accurate timing information and renders neighbor discovery more energy efficient. The designed protocols improve the lifetime of mobile devices in DTNs by means of energy efficient neighbor discoveries that reduce the energy waste caused by idle listening problems.

This research investigates cross-layer design in multi-hop wireless networks with random access. Due to the complexity of the problem, we study cross-layer design with a simple slotted ALOHA medium access control (MAC) protocol without considering any network dynamics. Firstly, we study the optimal joint configuration of routing and MAC parameters in slotted ALOHA based wireless networks under a signal to interference plus noise ratio based physical interference model. We formulate a joint routing and MAC (JRM) optimization problem under a saturation assumption to determine the optimal max-min throughput of the flows and the optimal configuration of routing and MAC parameters. The JRM optimization problem is a complex non-convex problem. We solve it by an iterated optimal search (IOS) technique and validate our model via simulation. Via numerical and simulation results, we show that JRM design provides a significant throughput gain over a default configuration in a slotted ALOHA based wireless network. Next, we study the optimal joint configuration of routing, MAC, and network coding in wireless mesh networks using an XOR-like network coding without opportunistic listening. We reformulate the JRM optimization problem to include the simple network coding and obtain a more complex non-convex problem. Similar to the JRM problem, we solve it by the IOS technique and validate our model via simulation. Numerical and simulation results for different networks illustrate that (i) the jointly optimized configuration provides a remarkable throughput gain with respect to a default configuration in a slotted ALOHA system with network coding and (ii) the throughput gain obtained by the simple network coding is significant, especially at low transmission power, i.e., the gain obtained by jointly optimizing routing, MAC, and network coding is significant even when compared to an optimized network without network coding. We then show that, in a mesh network, a significant fraction of the throughput gain for network coding can be obtained by limiting network coding to nodes directly adjacent to the gateway. Next, we propose simple heuristics to configure slotted ALOHA based wireless networks without and with network coding. These heuristics are extensively evaluated via simulation and found to be very efficient. We also formulate problems to jointly configure not only the routing and MAC parameters but also the transmission rate parameters in multi-rate slotted ALOHA systems without and with network coding. We compare the performance of multi-rate and single rate systems via numerical results. We model the energy consumption in terms of slotted ALOHA system parameters. We found out that the energy consumption for various cross-layer systems, i.e., single rate and multi-rate slotted ALOHA systems without and with network coding, are very close.

This thesis presents the potential of integrating chemical and biological treatment technologies for the removal of high concentrations of phenol in a bioremediation medium. High concentrations of phenol in wastewater are difficult to remove by purely biological methods. Chemical oxidation is one way to treat high concentrations of phenol but complete oxidation is not always possible or will make the treatment process uneconomical. An experimental design approach, based on central composite rotatable design (CCRD) was used to evaluate the effects of process parameters on phenol oxidation by Fentons reagent and chlorine dioxide. Performance of the chemical oxidation was evaluated by determining the percentage of phenol oxidized at equilibrium. The reaction mechanism for the oxidation of phenol by Fentons reagent was proposed based on identification of the intermediate compounds.<p> The effects of H₂O₂ concentration (2000 to 5000 mg L^-1) and FeSO₄.7H₂O concentration (500 to 2000 mg L^-1) were investigated on phenol oxidation and optimal concentrations of H₂O₂ and FeSO₄.7H₂O for complete oxidation of 2000 mg L^-1 phenol in medium were found to be 4340 mg L^-1 and 1616 mg L^-1, respectively, at 25°C and pH 3. The main oxidation products were identified as catechol, hydroquinone and maleic acid.<p> In the case of phenol oxidation by chlorine dioxide, the effects of chlorine dioxide concentration (500 to 2000 mg L^-1), temperature (10 to 40°C) and pH (3 to 7) on the oxidation of 2000 mg L^-1 of phenol were determined. The optimal concentration of chlorine dioxide to completely oxidize 2000 mg L^-1 of phenol was 2000 mg L^-1. The other parameters did not significantly affect the oxidation over the ranges studied. The main oxidation products were identified as 1,4-benzoquinone and 2-chloro-1,4-benzoquinone.<p> Finally, the biodegradation of 1,4-benzoquinone, the main oxidation product of phenol oxidation by chlorine dioxide, was studied in batch and continuous systems using Pseudomonas putida 17484 in two dose McKinneys medium. The effects of 1,4-benzoquinone concentration and temperature were studied on biodegradation of 1,4-benzoquinone in batch reactors. Under optimal conditions, it was found that 150 mg L^-1 1,4-benzoquinone could be successfully biodegraded at 15°C. In a continuous reactor operating at 15°C the highest removal rate with 500 mg L^-1 of 1,4-benzoquinone was found to be 246 mg L^-1 h^-1. The values of µmax, Ks and yield were also determined as 0.74±0.03 h^-1 and 14.17±3.21 mg L^-1 and 2x10¹³ cell mg^-1, respectively.

The purpose of this thesis is to describe the behaviors that multinational corporations(MNCs) and small and medium-sized enterprises (SMEs) are taking for carrying outcorporate social responsibility (CSR) under the context of sustainable development.Besides, the factors which drive and influence the performance are further exploredand discussed.The thesis is to be analyzed by means of a literature review, qualitative case study,semi-structured interviews, within case study and cross case study.By adopting these methods, the thesis shows that both MNCs and SMEs are aware ofand actively shouldering CSR in spite of different contents and approaches. MNCs areable to integrate economic, environment and social values into CSR strategy whileSMEs focus more on economic values. Competitive pressures, social expectations andinternal governance system are the main drivers of MNCs. By contrast, owners’ desiregives rise to the performance of carrying out CSR strategy by SMEs.It is suggested that a new domain of CSR namely, political social responsibility isfound through the study. It demonstrates that MNCs with the state-owned nature haveparticular missions and responsibilities to serve the country and society, which is notcommon but exists in the world.

The large accounting scandals in the early 21st century had large impact on the future discussion regarding the importance of auditor independence. This led to stricter auditor independence rules in Sweden as well as internationally. Small and medium-sized enterprises frequently hire their auditor for consulting services. A long and close audit-client relationship is common for small and medium sized enterprises. This is considered to be a threat towards the auditor independence. The purpose of this thesis is to examine whether Swedish small and medium sized enterprises, who are required to be audited, are aware of the auditor independence regulations. The thesis further aims analyze if the regulation of audit independence is as necessary for small companies as for large companies with additional number of shareholders. A qualitative study has been performed where data has been collected through 102 telephone interviews with small and medium-sized companies. A questionnaire consisting of both multiple choice and open questions has been used for the interviews. The collected data were compiled in SPSS which generated graphs and tables that then were analyzed. Small and medium-sized companies believe it is important that the auditor is independent towards their company. On the other hand, management in Swedish small and medium-sized enterprises has no direct knowledge of what the auditor independence regulation implies. / De stora redovisningsskandalerna i början av 2000-talet fick stor betydelse för den kommande diskussionen angående vikten av revisorns oberoende. Detta ledde till strängare regler för revisorerna i Sverige såväl som internationellt. Revisorn fungerar i många små och medelstora företag som en ekonomisk rådgivare. Små företag har ofta en lång och nära relation med sin revisor. Detta anses vara ett hot mot revisorns oberoende. Syftet med denna uppsats är att undersöka om revisionspliktiga små och medelstora företag är medvetna om reglerna gällande revisorns oberoende. Uppsatsen avser vidare att analysera om reglerna för revisorns oberoende är lika nödvändiga för små företag som för stora företag med en stor andel aktieägare. En kvalitativ undersökning har utförts där data från 102 telefonintervjuer med små och medelstora företag har samlats in. Ett frågeformulär med både flersvarsfrågor och öppna frågor har legat som grund för undersökningen. Den insamlade datan sammanställdes i SPSS vilket genererade grafer och tabeller som sedan analyserades. Små och medelstora företag anser att det är viktigt att revisorn är oberoende gentemot deras företag. Å andra sidan har ledningen i svenska små och medelstora företag ingen direkt kunskap om vad revisorns oberoende reglering innebär.

This dissertation examines the role of social media in the communication process of small and medium-sized enterprises (SMEs). Based on communication and social media theories, this study examines how small and medium-sized enterprises incorporate social media in their marketing and communication strategy. As a result, this study concludes that social media has an important role in the communication process of SMEs. The study shows, that to increase a two-way communication via social media, SMEs must focus more on enabling interactions, to collect responses and feedback. A professional appearance on the platforms has been considered as crucial. The results additionally show that SMEs recognize space and need for improvement of their social media skills. The integration of social media into the overall concept differs among the cases. A major obstacle can be found regarding the detection of target groups on social media. Moreover, a lack of strategic orientation can be found in terms of social media goals and budgets, as well as performance measurement.

Small and medium enterprises has attracted a wide argument and debate by scholars and other interest group as to whether they have significant contribution to employment creation or not. Many researchers have taken up to this field of research with different opinion and research finding. This thesis focuses on establishing the barriers to expansion and growth of small and medium enterprises in Gotland region of Sweden. The research focus on interview of business owners and managers in the region, a total of 25 business managers were interviewed and their response used to draw conclusion in this thesis. The research focused on finding out the number of employees in each of the company or business interviewed; reasons for not employing more people in their businesses and possible barriers and difficulties they experience in their business operation. The thesis was able to establish the fact that SME contributes to employment creation in the region and that the number of SME start up in the region is on the increase which has a correlation with increase in employment via SMEs in the region. Furthermore, some factors were identified as major barriers to creation of more jobs by SMEs in the region base on the information elicited from the managers interviewed. Finally, recommendations for future research were made on possible steps the Government can employ to address the problems outlined that inhibit expansion and creation of more jobs by the SME sector in the region.

Hilma af Klint är en av de mest uppmärksammade kvinnliga konstnärerna ur sin tid trots ellerkanske på grund av att hennes bilder inte uppmärksammades förrän 45 år efter hennes död. Detta faktum samt att en stor del av hennes livsverk var andliga, mediumstiskt framställda bilder gör dets vårt att placera bilderna i en konsthistorisk kontext. I denna C-uppsats undersöker jag framförallttre aspekter runt Hilma af Klints och hennes livsverk med tempelbilderna. Jag har med hjälp avqueerteorier undersökt hur utanförskap och avsaknad av sexualitet kan ha påverkat Hilma af Klintsbildskapande. Jag har intresserat mig för en roll som Hilma af Klints bilder tycks ha, som kartor och manualer för andra andliga sökare. Hon var en bildskapare som levde utanför de rådande normerna både vad gäller bildskapandet och personligen och gick sin egen väg vilket gör henne till eninspiratör för de som kommer efter henne. Hilma af Klint levde asketiskt helt hängiven sitt uppdrag. Allt tyder på att hon levde utan partner i avhållsamhet trots att hennes viktigaste budskap var ”dualen” som innebär att mannen och kvinnan är två halvor av samma själ som letar efter varandraför att återförenas. I bilderna framställs dualen som en man och en kvinna medan i Hilma af Klints anteckningar visar det sig att hon upplevde en kvinna som hennes dual under en tid medan det vid ett annat tillfälle var en man ur andevärlden. En annan aspekt som jag undersökt är hur bilderna uppfattas när de inte hamnar i den tempelmiljö som de skapades för och istället betraktas som autonoma. Tidigare forskning innehåller inga bildanalyser vilket jag tagit fasta på och anser vara enviktig del av att förstå bilder som autonoma, en viktig aspekt av modernistisk konst. I dessa bildanalyser finner jag att bilderna har mycket att ge om de tillåts stå fria från det sammanhang somde skapandes ur. Ytterligare en aspekt som jag undersökt är hur dessa bilder behandlas i konsthistorieskrivningen. Hilma af Klint upplevde sig som en förmedlare av bilder från andliga mästare, hennes egen roll som subjekt var sekundär. Trots detta är det personen Hilma af Klint som fått mest utrymme i historieskrivningen. Det finns en gängse bild av Hilma af Klint som en pionjär inom den abstrakta konsten vilket kan ses som problematiskt av flera skäl, inte minst det faktum att bilderna, enligt henne själv, var förmedlade till henne i syfte att upplysa mänskligheten. Jag har funnit att det tyvärr inte är helt enkelt att uppleva Hilma af Klints bilder i original. Tempelbildernavar tänkta att smycka ett tempel som aldrig kom att byggas. Ingen, inte ens Hilma af Klint själv har sett Tempelbilderna samlade i sin tänkta miljö. Däremot finns det planer på ett museum i Ytterjärna som enligt uppgift ska visa hela Hilma af Klints livsverk.