SwePub
Sök i SwePub databas

  Utökad sökning

Träfflista för sökning "LAR1:hh srt2:(2005-2009);srt2:(2007);mspu:(licentiatethesis)"

Sökning: LAR1:hh > (2005-2009) > (2007) > Licentiatavhandling

  • Resultat 1-3 av 3
Sortera/gruppera träfflistan
   
NumreringReferensOmslagsbildHitta
1.
  • Nilsson, Björn, 1965- (författare)
  • Towards energy efficient protocols for active RFID
  • 2007
  • Licentiatavhandling (övrigt vetenskapligt/konstnärligt)abstract
    • The absence of a global standard is a bottleneck when using Radio Frequency Identification (RFID) technology. This thesis explores data communication protocols for Active-RFID regarding their energy efficiency and how they can be suited to fit a large variety of applications.The use of Radio Frequency Identification systems (RFID) is growing rapidly. Today mostly "passive" RFID systems are used because no onboard energy source is needed on the transponders. However, "active" RFID technology, with onboard power sources in the transponders, gives a range of opportunities not possible with passive systems. Besides that Active RFID offers longer working distance between RFID-reader and tag than passive RFID, this also enables the tags to do sensor measurements, calculations and storage even when no RFID-reader is in the vicinity of the tags.To obtain energy efficiency in an Active RFID system the data communication protocol to be used should be carefully designed with energy optimization in mind. This thesis describes how energy consumption can be calculated, to be used in protocol definition, and how evaluation of protocols in this respect can be made. The performance of such a new protocol, in terms of energy efficiency, aggregated throughput, delay, and number of air collisions is evaluated and compared to an existing, commercially available protocol for Active RFID, as well as the IEEE standard 802.15.4 (used e.g. in the Zigbee medium-access layer). Simulations show that, by acknowledging the payload and using deep sleep mode on the tag, the lifetime of a tag is increased.For all types of protocols using an air channel for transmitting and receiving information it is obvious that the utilization of the channel is maximized when no collisions occur. To avoid and minimize collisions in the air interface it is possible to listen to the channel (carrier sense) and know its status. Knowing that the channel is occupied should result in a back-off and a later retry, instead of persistently listening to the channel which would require constant energy consumption. We further study the effect on tag energy cost and packet delay incurred by some typical back-off algorithms (constant, linear, and exponential) used in a contention based CSMA/CA (Carrier Sense Multiple Access/Collision Avoidance) protocols for Active RFID communication. The study shows that by selecting the proper back-off algorithm coefficients (based on the number of tags), i.e. the initial contention window size and back-off interval coefficient, the tag energy consumption and read-out delays can be significantly lowered.
  •  
2.
  • Rundquist, Jonas, 1964- (författare)
  • Outsourcing of New Product Development - A decision framework
  • 2007
  • Licentiatavhandling (övrigt vetenskapligt/konstnärligt)abstract
    • The focus of this thesis is the outsourcing of activities in the New Product Development (NPD) process. Outsourcing of NPD refers to the outsourcing of development activities for the developing of new products (goods and/or service), where all or just the innovative part of the NPD process is purchased externally based on a contract with organizational units separate from the outsourcing firm. This definition implies that (A) the activity should be an innovative part of the NPD process, (B) the activity should have previously been conducted internally, and (C) the activity should be purchased under a contractual agreement between the organizations.This thesis focuses on the outsourcing of NPD in medium sized firms. Although the framework is probably also useful for small and large firms, the three empirical studies in the thesis explored samples of medium sized firms. NPD is a knowledge intensive activity that requires the ability to handle uncertainties and is very dependent on the individuals involved in the process. In this way it differs from production, which (especially when producing standard items on a large scale) is easier to control, monitor and to evaluate the costs. Therefore, some considerations connected to knowledge acquisition and uncertainty needs to be addressed.A literature review reveals that research on outsourcing often focuses on A) Large firms and B) outsourcing of production activities. In addition, research on NPD usually involves large firms, despite the fact that the interest in product development in small and medium sized firms has grown rapidly in recent years. Since outsourcing of NPD is a method frequently used to access competence, and reduce costs and/or uncertainty, it seems motivated to study the outsourcing of NPD in medium sized firms.The thesis presents a decision framework that is based on three empirical studies (two survey studies and one case study) and a theoretical framework. The theoretical framework presented in the thesis is commonly used to understand outsourcing questions in general. In the present thesis the framework is applied in the specific situation of outsourcing a knowledge intensive activity (such as NPD) in the context of medium sized firms. Transactions cost, resource based, resource dependency, knowledge based, agency cost, and institutional theories are revisited in the thesis.Outsourcing can lead to advantages in form of lower costs, access to knowledge or other resources, as well as access to markets, but it can also result in a knowledge drain, lower motivation among in-house staff, or an increased level of dependency on external organizations. Therefore the decision to outsource is not always a good one, and the pros and cons must be carefully evaluated. The result of the thesis is a decision framework that maps factors affecting the decisions that need to be made when outsourcing NPD. The implications can be of value to the outsourcing firm as well as to the potential outsourcing partner. The framework has been presented to the firms in the studies and thus has already proved its value to some extent.The framework will also be used for the design of the studies that will hopefully take me towards my PhD degree, including a new survey study as well as a case study focusing on knowledge integration.
  •  
3.
  • Teferi Lemma, Dereje, 1069- (författare)
  • Audio-video synthesis methods for improving performance of biometric systems
  • 2007
  • Licentiatavhandling (övrigt vetenskapligt/konstnärligt)abstract
    • System security is important for any automation. It is even more so in the case of biometric systems due to the sensitive nature of the data it uses for enrollment and authentication - the subjects physical or biological trait. The performance quantification of biometric systems, such as face tracking and recognition, highly depend on the database used for testing the systems. Systems trained and tested on realistic and represenative databases evidently perform better. In fact, the main reason for evaluating any system on test data is that these data sets represent problems that system might face in the real world. However, building biometric databases that represent the real world is an expensive task due to its high demand on the side of the participants. This becomes even more difficult and unrealistic if the data is to be collected in a natural environment such as supermarkets, offices, streets, etc.This thesis presents a procedure to build a synthetic biometric database by damascening images from a studio recorded database with a realistic scenery. To this end, we developed an image segmenation procedure to spearate the background of a video recorded in studio conditions with the prupose to replace it with an arbitrary complex background. Furthermore, we present how several degradations such as affine transformation, imaging noise, and motion blur can be incorporated into the production of the new database to simulate natural recording environments. The system is applied to the entire XM2VTS database, which already consists of several terabytes of data, to produce the DXM2VTS - Damascened XM2VTS database.Moreover, the thesis presents a method to segment a video sequence in the time domain based on its audio concept. The video is then reshuffled and used for testing resilience of text-prompted biometric systems against playback attacks. The playback is supported by pyramid based frame interpolation method to reduce discontinuities created at the digit boundaries in time.
  •  
Skapa referenser, mejla, bekava och länka
  • Resultat 1-3 av 3
Typ av publikation
Typ av innehåll
övrigt vetenskapligt/konstnärligt (3)
Författare/redaktör
Rundquist, Jonas, 19 ... (1)
Bigun, Josef, Profes ... (1)
Nilsson, Björn, 1965 ... (1)
Teferi Lemma, Dereje ... (1)
Lärosäte
Högskolan i Halmstad (3)
Chalmers tekniska högskola (1)
Språk
Engelska (3)
Forskningsämne (UKÄ/SCB)
Naturvetenskap (2)
Teknik (1)
Samhällsvetenskap (1)
År

Kungliga biblioteket hanterar dina personuppgifter i enlighet med EU:s dataskyddsförordning (2018), GDPR. Läs mer om hur det funkar här.
Så här hanterar KB dina uppgifter vid användning av denna tjänst.

 
pil uppåt Stäng

Kopiera och spara länken för att återkomma till aktuell vy