Performance issues in mid-sized relational database machines

Relational database systems have provided end users and application programmers with an improved working environment over older hierarchial and networked database systems. End users now use interactive query languages to inspect and manage their data. And application programs are easier to write and maintain due to the separation of physical data storage information from the application program itself. These and other benefits do not come without a price however. System resource consumption has long been the perceived problem with relational systems. The additional resource demands usually force computing sites to upgrade existing systems or add additional facilities. One method of protecting the current investment in systems is to use specialized hardware designed specifically for relational database processing. \u27Database Machines\u27 provide that alternative. Since the commercial introduction of database machines in the early 1980\u27s, both software and hardware vendors of relational database systems have claimed superior performance over competing products. Without a STANDARD performance measurement technique, the database user community has been flooded with benchmarks and claims from vendors which are immediately discarded by some competitors as being biased towards a particular system design. This thesis discusses the issues of relational database performance measurement with an emphasis on database machines, however; these performance issues are applicable to both hardware and software systems. A discussion of hardware design, performance metrics, software and database design is included. Also provided are recommended guidelines to use in evaluating relational database systems in lieu of a standard benchmark methodology

Moving Beyond Tradition: Designing an Online Course for School Leaders

Increasingly post-secondary institutions are dedicating resources to develop online courses. This includes hybrid (classroom and online instruction) and fully online classes. The growth of online options coincides with the creation of various platforms that make communication between graduate students and faculty members seamless. However, there is a gap in the research which examines the development of online courses for current and aspiring school leaders (e.g., teachers, principals, district staff). For this reason, this article utilizes extant literature and autoethnographic vignettes to 1) investigate the steps universities and school districts should take to make online classes more accessible for school leaders; 2) discuss the advantages and challenges of taking online classes for school leaders and 3) describe a faculty members experience developing a graduate online course. The article includes limitations and implications

Leadership Matters: Supporting the Mental Health Needs of Black and Latina/o Students in a Post COVID-19 World

Communities throughout the United States were devastated by the COVID-19 virus. For instance, the mortality rates are higher within Black and Latina/o communities compared to the overall United States population. The pandemic represents another problem that will contribute to anxiety disorders and depression among Black and Latina/o students. How we combat these issues is important. During the 2020-2021 school year millions of students returned to schools and some struggled to adjust because of the traumatic experiences associated with COVID-19. Students will need the support of administrators, teachers, and mental health practitioners. For this reason, this review of literature examined the mental health challenges Black and Latina/o students encountered prior to and during the pandemic. Further, the authors developed recommendations for school leaders, mental health specialists, and teachers while providing important resources. Overall leaders can use the article as a roadmap to navigate the challenges at PreK-12 schools

Towards a millivolt optical modulator with nano-slot waveguides

We describe a class of modulator design involving slot waveguides and electro-optic polymer claddings. Such geometries enable massive enhancement of index tuning when compared to more conventional geometries. We present a semi-analytic method of predicting the index tuning achievable for a given geometry and electro-optic material. Based on these studies, as well as previous experimental results, we show designs for slot waveguide modulators that, when realized in a Mach-Zehnder configuration, will allow for modulation voltages that are orders of magnitude lower than the state of the art. We also discuss experimental results for nano-slot waveguides

Summary of LDEF battery analyses

Tests and analyses of NiCd, LiSO2, and LiCf batteries flown on the Long Duration Exposure Facility (LDEF) includes results from NASA, Aerospace, and commercial labs. The LiSO2 cells illustrate six-year degradation of internal components acceptable for space applications, with up to 85 percent battery capacity remaining on discharge of some returned cells. LiCf batteries completed their mission, but lost any remaining capacity due to internal degradation. Returned NiCd batteries tested an GSFC showed slight case distortion due to pressure build up, but were functioning as designed

Punish Them or Engage Them? Teachers’ Views of Unproductive Student Behaviours in the Classroom

This paper reports on a study that investigated the extent to which student behaviour is a concern for school teachers. A questionnaire was used to investigate teachers’ views about student behaviour in their classes. The results suggest that low-level disruptive and disengaged student behaviours occur frequently and teachers find them difficult to manage. Aggressive and anti-social behaviours occur infrequently. Teachers employ strategies to manage unproductive behaviours that locate the problem with the student. This paper argues that teachers could benefit from understanding how the classroom ecology influences engagement and therefore student behaviour, rather than focusing on ‘fixing’ unproductive behaviour

Inter-agency Working Group for Airborne Data and Telemetry Systems (IWGADTS)

The Interagency Coordinating Committee for Airborne Geosciences Research and Applications (ICCAGRA) was established to improve cooperation and communication among agencies sponsoring airborne platforms and instruments for research and applications, and to serve as a resource for senior level management on airborne geosciences issues. The Interagency Working Group for Airborne Data and Telecommunications Systems (IWGADTS) is a subgroup to ICCAGRA for the purpose of developing recommendations leading to increased interoperability among airborne platforms and instrument payloads, producing increased synergy among research programs with similar goals, and enabling the suborbital layer of the Global Earth Observing System of Systems

Concurrent panel session 2: Challenges facing our youth and aged populations

Moderator: Dr. Ann McDonough, UNLV Gerontology Program Scribe: Lisa Gioia-Acres, UNLV Department of History Conference white paper & Full summary of panel session, 4 page

Altair Descent and Ascent Reference Trajectory Design and Initial Dispersion Analyses

The Altair Lunar Lander is the linchpin in the Constellation Program (CxP) for human return to the Moon. Altair is delivered to low Earth orbit (LEO) by the Ares V heavy lift launch vehicle, and after subsequent docking with Orion in LEO, the Altair/Orion stack is delivered through translunar injection (TLI). The Altair/Orion stack separating from the Earth departure stage (EDS) shortly after TLI and continues the flight to the Moon as a single stack. Altair performs the lunar orbit insertion (LOI) maneuver, targeting a 100-km circular orbit. This orbit will be a polar orbit for missions landing near the lunar South Pole. After spending nearly 24 hours in low lunar orbit (LLO), the lander undocks from Orion and performs a series of small maneuvers to set up for descending to the lunar surface. This descent begins with a small deorbit insertion (DOI) maneuver, putting the lander on an orbit that has a perilune of 15.24 km (50,000 ft), the altitude where the actual powered descent initiation (PDI) commences. At liftoff from Earth, Altair has a mass of 45 metric tons (mt). However after LOI (without Orion attached), the lander mass is slightly less than 33 mt at PDI. The lander currently has a single descent module main engine, with TBD lb(sub f) thrust (TBD N), providing a thrust-to-weight ratio of approximately TBD Earth g's at PDI. LDAC-3 (Lander design and analysis cycle #3) is the most recently closed design sizing and mass properties iteration. Upgrades for loss of crew (LDAC-2) and loss of mission (LDAC-3) have been incorporated into the lander baseline design (and its Master Equipment List). Also, recently, Altair has been working requirements analyses (LRAC-1). All nominal data here are from the LDAC-3 analysis cycle. All dispersions results here are from LRAC-1 analyses