Systems Engineering Model and Training Application for Desktop Environment

Provide a graphical user interface based simulator for desktop training, operations and procedure development and system reference. This simulator allows for engineers to train and further understand the dynamics of their system from their local desktops. It allows the users to train and evaluate their system at a pace and skill level based on the user's competency and from a perspective based on the user's need. The simulator will not require any special resources to execute and should generally be available for use. The interface is based on a concept of presenting the model of the system in ways that best suits the user's application or training needs. The three levels of views are Component View, the System View (overall system), and the Console View (monitor). These views are portals into a single model, so changing the model from one view or from a model manager Graphical User Interface will be reflected on all other views

Optimizing Thermoelectric Efficiency in La_(3−x)Te_4 via Yb Substitution

A low temperature, solid state synthesis technique has enabled the production of homogeneous samples of La_(3−x−y)Yb_yTe_4. This allows the substitution of divalent Yb to be utilized to optimize the thermoelectric performance in lanthanum telluride. The addition of Yb^(2+) changes the electrical transport properties in a manner that can be well understood using valence counting rules and a corresponding change in the Fermi energy. The substitution of Yb^(2+) for La^(3+) results in a threefold finer control over the carrier density n, thus allowing the optimum n ~ 0.3 × 10^(21) cm^(−3) to be both predicted and prepared. The net result is an improvement in thermoelectric efficiency, with zT reaching ~ 1.2 at 1273 K

Zintl Chemistry for Designing High Efficiency Thermoelectric Materials

Zintl phases and related compounds are promising thermoelectric materials; for instance, high zT has been found in Yb_(14)MnSb_(11), clathrates, and the filled skutterudites. The rich solid-state chemistry of Zintl phases enables numerous possibilities for chemical substitutions and structural modifications that allow the fundamental transport parameters (carrier concentration, mobility, effective mass, and lattice thermal conductivity) to be modified for improved thermoelectric performance. For example, free carrier concentration is determined by the valence imbalance using Zintl chemistry, thereby enabling the rational optimization of zT. The low thermal conductivity values obtained in Zintl thermoelectrics arise from a diverse range of sources, including point defect scattering and the low velocity of optical phonon modes. Despite their complex structures and chemistry, the transport properties of many modern thermoelectrics can be understood using traditional models for heavily doped semiconductors

Transport properties of the layered Zintl compound SrZnSb_2

Transport properties of the layered Zintl compound SrZnSb_2 have been characterized from room temperature to 725 K on polycrystalline samples. SrZnSb_2 samples were found to be p-type with a Hall carrier concentration of 5×10^(20) cm^(−3) at room temperature, and a small Seebeck coefficient and electrical resistivity are observed. A single band model predicts that, even with optimal doping, significant thermoelectric performance will not be achieved in SrZnSb_2. A relatively low lattice thermal conductivity is observed, κ_L~1.2 W m^(−1) K^(−1), at room temperature. The thermal transport of SrZnSb_2 is compared to that of the layered Zintl compounds AZn2Sb_2 (A=Ca,Yb,Sr,Eu), which have smaller unit cells and larger lattice thermal conductivity, κ_L~2 W m^(−1) K^(−1), at 300K. Ultrasonic measurements, in combination with kinetic theory and the estimated κ_L values, suggest that the lower κ_L of SrZnSb_2 is primarily the result of a reduction in the volumetric specific heat of the acoustic phonons due to the increased number of atoms per unit cell. Therefore, this work recommends that unit cell size should be considered when selecting Zintl compounds for potential thermoelectric application

Diurnal ocean surface layer model validation

The diurnal ocean surface layer (DOSL) model at the Fleet Numerical Oceanography Center forecasts the 24-hour change in a global sea surface temperatures (SST). Validating the DOSL model is a difficult task due to the huge areas involved and the lack of in situ measurements. Therefore, this report details the use of satellite infrared multichannel SST imagery to provide day and night SSTs that can be directly compared to DOSL products. This water-vapor-corrected imagery has the advantages of high thermal sensitivity (0.12 C), large synoptic coverage (nearly 3000 km across), and high spatial resolution that enables diurnal heating events to be readily located and mapped. Several case studies in the subtropical North Atlantic readily show that DOSL results during extreme heating periods agree very well with satellite-imagery-derived values in terms of the pattern of diurnal warming. The low wind and cloud-free conditions necessary for these events to occur lend themselves well to observation via infrared imagery. Thus, the normally cloud-limited aspects of satellite imagery do not come into play for these particular environmental conditions. The fact that the DOSL model does well in extreme events is beneficial from the standpoint that these cases can be associated with the destruction of the surface acoustic duct. This so-called afternoon effect happens as the afternoon warming of the mixed layer disrupts the sound channel and the propagation of acoustic energy

A Holistic Approach for Enriching Information Security Analysis and Security Policy Formation

Past literature has indicated the need for addressing information security from both the social and technical perspective. However, previous research has lacked in providing any clear direction for how these two perspectives can be brought together in a coherent or holistic manner to analyze information security in an organization. Thus, this paper develops a conceptual framework for identifying, bringing together, and interpreting the deep-rooted social and technical issues that pertain to information systems security. The framework is grounded in semiotics and is validated by the analysis of a specific case study. Findings in this research indicate that the social and technical elements of security can be brought together in a holistic manner via six layers of abstraction where each layer addresses deep-rooted issues that pertain to information security. The output of each layer is then used to inform other layers in a collaborative manner creating a final product that contains elements for enriching security analysis and enhancing security policy formation

Interpreting Beyond Syntactics: A Semiotic Learning Model for Computer Programming Languages

In the information systems field there are numerous programming languages that can be used in specifying the behavior of concurrent and distributed systems. In the literature it has been argued that a lack of pragmatic and semantic consideration decreases the effectiveness of such specifications. In other words, to simply understand the syntactic features of a programming language alone does not provide an adequate foundation for students, programmers and designers to learn or to create robust and efficient programs. As a result, this paper will present a fresh approach for both teaching and understanding programming languages. The approach presented in this paper uses semiotics as a theoretical lens for identifying the important issues that transcend syntax issues alone and creates an organized conceptual model that will force instructors to facilitate a deeper understanding of programming constructs to their students

Using Activity Diagrams to Model Systems Analysis Techniques: Teaching What We Preach

Activity diagrams are used in Systems Analysis and Design classes as a visual tool to model the business processes of ‘as- is’ and ‘to-be’ systems. This paper presents the idea of using these same activity diagrams in the classroom to model the actual processes (practices and techniques) of Systems Analysis and Design. This tip accomplishes three things: (1) helps students better understand the purpose of drawing activity diagrams, (2) illustrates how useful activity diagrams are in understanding and communicating techniques and business processes at both high and low levels, and (3) teaches the various systems analysis and design practices and techniques in a creative manner that visual learners will appreciate

Thermoelectric properties of p-type LiZnSb: Assessment of ab initio calculations

In response to theoretical calculations on the thermoelectric performance of LiZnSb, we report the pertinent transport properties between room temperature and 523 K. Nominal LiZnSb samples are found to be p-type, with a carrier concentration in the range (4–7)×10^(20) cm^(−3). The thermoelectric figure of merit (zT) is found to be 0.02–0.08 at 523 K. Analysis of material transport parameters and previously reported ab initio calculations demonstrates that even with optimal doping, p-type LiZnSb is unlikely to achieve zT>0.2 at 523 K. The accuracy of the high zT estimate (zT>2) for n-type compositions from ab initio calculations is discussed within the current synthetic limits

Play Ball: Bringing Scrum into the Classroom

Scrum has become a widely-used framework for technology development in both private industry and the government. As a result, Information Systems recruiters and executives have recently been placing a focus on students with Scrum knowledge. Unfortunately, current System Analysis and Design textbooks provide cursory attention to Scrum. Thus, the purpose of this paper is to suggest a starting point for teaching Scrum at the university level by presenting a classroom exercise (Ball Game) that can be used as a means for learning Scrum in more detail. This tip accomplishes three things: (1) introduces students to Scrum concepts with an engaging and memorable exercise, (2) provides a means for teaching students about estimation, and (3) offers an approach that allows students to witness firsthand how self-organized teams inspect, adapt, and evolve