Packet Aggregation in TelosB WSNs: Design, Implementation and Experiments

Master's thesis in Information- and communication technology IKT590 - University of Agder 2016WSN is an extensive field of research and a core technology which is adopted for monitoring and data assembling, used in various applications. Traditionally in a WSN, communication is performed in the fashion of single packet per transmission which produces high energy consumption and longer delay. Therefore, we introduce a novel approach by designing a system which applies packet aggregation in TelosB sensor motes using Contiki platform. In this approach, we assemble multiple packets together and send them in an aggregated frame towards the sink which can reduce the number of transmissions, energy consumption and delay per transmission unit. Accordingly, in this thesis report, we perform aggregation at relay node with diverse set of topologies and schemes and examined this technique through numerous experiments and testing for temporal and spatial aggregation topologies. Additionally, we design and implement three packet aggregation schemes and perform a comprehensive set of experiments to evaluate these schemes. These experiments are capable to demonstrate how packet aggregation proposes compelling performance boost in terms of less transmission count and how these schemes strongly actuate the energy level due to the reduction in transmission count. This report concludes with a brief summary of these experiments and recommends some potential approaches to affirm and further expand these outcomes. We have a belief that this research will be effective for better understanding of packet aggregation approach in WSN for future pioneers

Motivating Tacit Knowledge Sharing: The Role of Perceived Value of Knowledge and Organizational Citizenship Behavior

Purpose: This study investigates the challenge of retaining and sharing tacit knowledge during employee transitions in organizations, with a specific focus on software developers' motivations. We examine two key motivational beliefs: the perceived value of knowledge and organizational citizenship behavior (OCB), and their influence on sharing intentions. Additionally, we explore how these beliefs shape attitudes, subsequently affecting intentions regarding tacit knowledge sharing.   Theoretical Framework: Grounded in the Theory of Reasoned Action (TRA), our research underscores the pivotal role of beliefs in shaping attitudes and intentions related to tacit knowledge sharing. Beliefs, encompassing the Perceived Value of Knowledge and OCB, play a significant role in molding attitudes. Using structural equation modeling, we analyze data collected from 197 software developers, employing confirmatory factor analysis to validate our measurement model and structural model analysis to explore relationships.   Findings: Our findings indicate that software developers are indeed willing to share their tacit knowledge, with their willingness positively influenced by the perceived value of tacit knowledge and engagement in OCB. Attitudes towards sharing tacit knowledge act as mediators in the relationship between these beliefs and sharing intentions.   Implications: In practical terms, organizations can foster tacit knowledge sharing by promoting positive attitudes, recognizing knowledge's perceived value, and cultivating a culture that encourages OCB. This facilitates a conducive environment for sharing, further enhanced by acknowledging and rewarding employees who exhibit OCB. Theoretical implications align with the Theory of Reasoned Action, emphasizing the role of attitude in shaping intentions. Our research contributes uniquely by exploring the underrepresented relationship between perceived knowledge value and tacit knowledge sharing, introducing a novel approach by examining the combined impact of OCB and perceived value. These insights are valuable for organizations looking to cultivate a culture of tacit knowledge sharing, driving innovation and enhancing performance

1-Azido-N′-(phenylsulfonyl)methan­imid­amide

In the title compound, C7H7N5O2S, the aromatic ring is oriented at dihedral angles of 79.46 (2) and 89.17 (2)°, respectively, with respect to the amino­(azido)­methyl and the S(6) six-membered ring motif generated by an intra­molecular N—H⋯O inter­action [N⋯O = 2.8901 (15) Å]. Inter­molecular N—H⋯O hydrogen bonds [N⋯O = 2.9177 (15) and 2.9757 (15) Å] generate an infinite one-dimensional network along the base vector (010)

Optimization and AMS Modeling for Design of an Electrostatic Vibration Energy Harvester’s Conditioning Circuit with an Auto-Adaptive Process to the External Vibration Changes

Electrostatic transducers for vibration energy scavenging have been an object to numerous studies, but are still facing major issues relating to their conditioning circuit. One of the most popular ones uses a charge pump and a flyback circuit based on a Buck DC-DC converter (Fig. 1). A commutation between the energy accumulation in the charge pump and the recharge of the buffer capacitor Cres is assured by a switch which is the major bottleneck in the energy harvester circuit. The commutation timing of the switch determines the efficiency of the energy harvesting. In previous papers [1] the switch commutates periodically with some fixed duty ratio. However, this solution is not appropriate when the environment parameters, e.g. the vibration frequency, change. We found that the switching should be ordered by the internal state of the circuit, an not by some fixed timing scenario. We presents how to find the optimal operation mode of the harvester. To validate the study, the system was modeled using a mixed VHDL-AMS - ELDO model

1-Ammonio­naphthalene-2-sulfonate

In the mol­ecule of the zwitterionic title compound, C10H9NO3S, an intra­molecular N—H⋯O hydrogen bond results in the formation of an almost planar six-membered ring (r.m.s daviation = 0.0150 Å), which is oriented at a dihedral angle of 1.63 (3)° with respect to the naphthalene ring system. In the crystal structure, inter­molecular N—H⋯O hydrogen bonds link the mol­ecules into a two-dimensional network

Laparoscopic sleeve gastrectomy - a prospective follow up of 30 patients

Background: Morbid obesity has become a surgically treatable problem. Laparoscopic sleeve gastrectomy is becoming a popular choice both for surgeons and patients due to effectiveness and low complication rates. Methods: It was a prospective case series spanning over 6 years. Patient enrolment started from January 2009 and data collection completed in January 2015.Patient with BMI (weight in kilogram/height in meter square) of more than 35 were included in the study. Follow up was at 2 weeks, 1 month, 6 months and 12 months. Success was defined as 25% of excess weight loss at 1 year. Paired t-test was used as a test of significance.Results:A total of 34 patients were included in the study over a 6-year period, 3 were lost to follow up and one patient died of cardiac arrest. Data of 30 patients is considered for final analysis. Mean age was 39.5±10 years, while mean BMI 45.8±6.3 (range 37.1–62.2). Average weight of the patients pre-operatively was 129.9±20.8 kg while mean excess weight was 70.3±20.8 kg. Average weight loss at two weeks was 8.9±2.9 kg, at one month 14.7±4.6 kg, at 6 months 25.0±7.6 kg and at twelve months was 31.4±6.8 kg. Mean percentage of excess weight loss after 2 weeks was 13.5±4.6%, at one month 22.0±6.1%, at six months 37.6±12.0% and at twelve months 47.3±10.1%. Conclusion:Laparoscopic sleeve gastrectomy is an effective weight loss surgery with minimal complications. On average weight loss of about 30 kg at one year was achieved which equals to almost half of excess body weight

The impact of surgical delay on resectability of colorectal cancer: An international prospective cohort study

AIM: The SARS-CoV-2 pandemic has provided a unique opportunity to explore the impact of surgical delays on cancer resectability. This study aimed to compare resectability for colorectal cancer patients undergoing delayed versus non-delayed surgery. METHODS: This was an international prospective cohort study of consecutive colorectal cancer patients with a decision for curative surgery (January-April 2020). Surgical delay was defined as an operation taking place more than 4 weeks after treatment decision, in a patient who did not receive neoadjuvant therapy. A subgroup analysis explored the effects of delay in elective patients only. The impact of longer delays was explored in a sensitivity analysis. The primary outcome was complete resection, defined as curative resection with an R0 margin. RESULTS: Overall, 5453 patients from 304 hospitals in 47 countries were included, of whom 6.6% (358/5453) did not receive their planned operation. Of the 4304 operated patients without neoadjuvant therapy, 40.5% (1744/4304) were delayed beyond 4 weeks. Delayed patients were more likely to be older, men, more comorbid, have higher body mass index and have rectal cancer and early stage disease. Delayed patients had higher unadjusted rates of complete resection (93.7% vs. 91.9%, P = 0.032) and lower rates of emergency surgery (4.5% vs. 22.5%, P < 0.001). After adjustment, delay was not associated with a lower rate of complete resection (OR 1.18, 95% CI 0.90-1.55, P = 0.224), which was consistent in elective patients only (OR 0.94, 95% CI 0.69-1.27, P = 0.672). Longer delays were not associated with poorer outcomes. CONCLUSION: One in 15 colorectal cancer patients did not receive their planned operation during the first wave of COVID-19. Surgical delay did not appear to compromise resectability, raising the hypothesis that any reduction in long-term survival attributable to delays is likely to be due to micro-metastatic disease

Outcomes from elective colorectal cancer surgery during the SARS-CoV-2 pandemic

This study aimed to describe the change in surgical practice and the impact of SARS-CoV-2 on mortality after surgical resection of colorectal cancer during the initial phases of the SARS-CoV-2 pandemic