I'm going to treat DS3s a little differently than I did T1s. While I believe knowledge
of T1 framing and signaling is useful for a network engineer, I don't feel that the
specifics are all that important when dealing with DS3s. For example, contrary to what many
people will tell you (often adamantly), a DS3 is not defined as 28 DS1s. A DS3 is actually
the result of multiplexing seven DS2s. If you're saying to yourself, "There's no such thing
as a DS2," you're not alone. A DS2 is a group of four DS1s, and is not seen outside of
While it may be interesting to know that a DS3 is composed of DS2s, that knowledge won't
help you build or troubleshoot a network today. In this chapter, I'll explain what you do
need to know about DS3s: simple theory, error conditions, how to configure them, and how to
A DS3 is not a T3.DS3 (Digital Signal 3) is the logical
carrier sent over a physical T3 circuit. In practice, the terms are pretty interchangeable;
most people will understand what you mean if you use either. However, from this point on,
I'll refer to the circuit simply as a DS3, as we're really interested in the circuit, and
not the physical medium.
Int'l Conf. Frontiers in Education: CS and CE | FECS'14 |
WUTexter: A Classroom Interaction Tool For Anybody Who Can
Benjamin Murray, Hunter LaTourette1, and Ron K. Cytron1
1 Department of Computer Science and Engineering, Washington University, St. Louis, Missouri, USA
Abstract— The classroom experience is enhanced for both teacher and student alike when feedback mechanisms are in place to measure the students’ engagement. Specialized devices such as the iClicker have been developed along these lines, but these devices have limited range and use.
This paper describes the design and implementation of a device that can be used within reach of the Internet or cell tower, allowing students to interact with the instructor in the classroom by sending simple text messages. The application currently accommodates polls, student-supplied questions, and a mechanism to express confusion or boredom. We provide some early anecdotal experiences using this device, articulate plans for the future, and describe how others can use this technology in their own settings.
At its simplest, flash photography is nothing more
complicated than lighting a scene with a single, brief burst of light.
Even so, flash photography has always been a very difficult technique to
master on any camera system.
This is largely because the human eye cant fully discern the
effects of a flash burst at the time an image is takenthe pulse of
light is just too short. Its also because small light sources can
produce a very unnatural form of light. Mastering flash, therefore,
requires two basic skills: the ability to understand how flash will
light a scene, and the ability to modify the intense, direct light to
best suit a photograph.
Most of this book is dedicated to describing how things work and
what tools are available. But if you want to get going right away, here
are some quick and easy starting points.
The EOS Rebel T1i or 500D camera (same product, different
markets) is an entry-level digital SLR camera. While it contains a
perfectly functional built-in popup flash unit, there is a lot of
versatility and power to be gained by adding an external flash
Dormitory, San Damiano (9:00 A.M., SEPTEMBER 1240) Sister Illuminata stood at one of the dormitory windows of San Damiano, gazing out at the Via Cupo di San Petrignano. She could not be seeing what she was seeing. The shouting that had drawn Illuminata to the window had materialized into a hoard of Saracen soldiers passing by the monastery. All of Assisi had feared the coming of these troops.
In Pisa, Illuminata had been a saddle maker’s daughter. She had admired the strong knights who patronized her father’s business, secretly believing that, like them, she would not flinch in the face of danger. Now her statuesque body was frozen with fear. She wanted to run, but there was nowhere to go.
Suddenly a horrific bashing shook the dormitory. Again.
“Mother!” The shriek came from Sister Angeluccia who had just raced up the stairs into the dormitory and who had thrown herself at Clare’s bedside. “The Saracens are battering the door of the church!”
“Quick, daughters!” Clare commanded from her sickbed. “Gather the sisters and bolt every door and window. Pull up the infirmary stairs! Have Sister Prassede bring the Body of the Lord! May God protect us!”