display, computers, and informatics

Polarizing lenses (how are they placed, what materials are between them. The on off state. 
What does that mean? You know, is there a current flowing? Is there no current flowing? 
Does that mean more like? Does it mean less light?

●Polarizing “lenses” use long, slender, aligned chains of iodine molecules which act as a grid

 

●Only those light waves (electrical component) which vibrate parallel to these chains of molecules can penetrate through. Perpendicular ones are blocked

The material between the two panels of an LCD monitor is nematic crystals and hydrogenated amorphous silicon

purpose of the fluorescent bulbs, the filter screens, LED bulbs.

Just to keep the monitor bright and uniformly bright

Know what stuck and dead pixels look like,

Truly dead pixels appear white, while stuck pixels appear dark

disadvantages of LCD monitors

• Limited contrast capability

• Biggest viewing angles

• brightness is kind of dependent on time and temperature

• can't show a true black, because there's always light

Know how luminance or light can be measured

• candela

• Nit

• Lux

what measures ambient lighting reflecting off the screen? How would that be measured?

Lux

Brightness of a light source

Luminance

what is the brightness of a light source within one storadium?

Lumen

how many sub pixels are in a pixel?

Three

Know a little bit about how the monochrome display monitor pixels work, you know, any advantages to owning a monochrome or using a monochrome?

For a monochrome display, each subpixel can be treated as a separately addressed element by the computer, producing entire range of gray levels from black to white, acting as a whole pixel

· The darkness of each subpixel can be controlled    by varying the voltage applied to it

Thus, for a monochrome display monitor, we acquire 3 functional pixels in the same space that a single pixel in a color monitor requires

 3 times higher resolution

Rods

• more numerous on the periphery of the retina

• Sensitive to low light levels and are stimulated during dim light situations

• Threshold for rod vision is 2 lux

Cones

• concentrated at the center of the retina in an area called the fovea centralis

• Less sensitive to light

• Threshold is approx 100 lux

• Capable of responding to intense light levels

Photo pic vision

Daylight vision

Scotopic vision

Night vision

Univac (universal automatic computer)

First commercially successful general purpose stored program electronic digital computer

Eniac

• electronic numerical integrator and calculator

• Contained more than 18,000 vacuum tubes that failed at an average rate of once every 7 minutes

Know how the transistor and vacuum tubes, kind of work.

• transistor is an electronic switch that alternately allows or does not allow electronic signals to pass

• Made possible the development of the stored program computer

I'm gonna ask one binary number and what number it represents

need to know difference between hexadecimal and ASCII code

Know what a raid system is

Backup

Redundant Array of Independent Disks

 

•Distributes copies of the same data files across several computer hard drives which are independent of each other, to assure that medical information or images are not lost by electrical failure, file corruption or software failure in a single system

 

•Before PACS, loss of medical documents was estimated at between 5 and 20 percent

bootstrap program. You need to know what kind of memory it would be an example of, like, is it ROM? 
Is it RAM? Is it EE prom?

• when the computer is first turned on, a program called a bootstrap, frozen permanently in read only memory (ROM), automatically opens

• Capable of transferring other necessary programs into the computer memory

• Loads the operating system into primary memory, which in turn controls all subsequent operations

know what the heart of the pacs is

• control computer

• PACS server

DICOM

Digital Imaging and Communication in Medicine

 

•Specifies only the transmission behavior of the various devices, not the specific architecture or terminology between different makes

•Main function of PAC system: Act as a database

Sample DICOM Commands:

 

•DICOM get worklist can generate lists of        patients or studies from the HIS or RIS

 

•DICOM query/retrieve can search out specific    images or studies

 

•DICOM send transmits data to the network

 

•DICOM print

The PACS system allows manipulation of the image:

 

•1. Windowing brightness and contrast

•2. Magnification & minification

•3. Annotation

 

•Web-based  PACS allow internet access

 

•Encryption software helps protect confidentiality

HL7

Health Level Seven Standard (HL7)

•Ongoing publication by Health Level Seven International since 1987 to standardize the way that health information is retrieved, exchanged, integrated, and shared

 

•HL7 is to medical information what DICOM is to medical images

Lossy

• provides compression factors up to 100 to 1 or greater

• Can be used on images in which exact measurement or fine detail is not required

Lossless

• can be reconstructed to be exactly the same as the original image

• Reduces the image date file to 10 percent to 50 percent

• Not satisfactory for large image files because transmission time and manipulation time can still be unacceptable

Baud rate

Speed of data transmisstion in bits per second (bps) or kilobits per second (Kps)

What do we call all the devices found in a network?

Nodes

know what the cosign law is

Maximum luminous intensity is achieved when viewing a monitor straight on. When a monitor is viewed from an angle, the contrast and the luminous intensity are reduced.

know what peripherals are, what's included in that

Peripherals are devices that connect to a computer but are not part of the core system (CPU and main memory). They expand what the computer can do.

They’re usually grouped into three main types:

1. Input devices (send data into the computer)

• Keyboard

• Mouse

• Scanner

• Microphone

• Webcam

2. Output devices (receive data from the computer)

• Monitor

• Printer

• Speakers

• Headphones

3. Storage devices (store data)

• USB flash drives

• External hard drives

• CDs/DVDs

know what a dumb terminal is and an intelligent terminal

• dumb terminal cannot do any processing on its own and it is used only to input data ir receive data from a main host computer

• Intelligent terminal has built in processing capability and RAM but does not have its own storage capacity

How many bytes make a bit?

8

Printers, which one has the highest resolution?

Inkjet

How many characters are in the hexa decimal code_

16

assemblers

• computer program that recognizes symbolic instructions such as subtract, load, and print, and translates them into the corresponding binary code

• Translation of a program written in symbolic, machine oriented instructions into machine language instructions

Compilers and interpreters

• computer programs that translate an application program from high level language into a form that is suitable for the assembler or into a form that is accepted directly by the computer

• Interpreters make program development easier because they are interactive

• Compiled programs run faster because they create a separate machine language program

What's another name for PACs

Mimps

WAN

wide area network (WAN) to remote    locations

Between locations

•May have several servers

•Publicly or commercially owned

•Usually employs phone or cable transmission services

LAN

local area network (LAN) to    workstations throughout the hospital, to doctors’    offices, or to radiologists’ home

: Within a location

•Usually only one server

•Usually privately owned

what kind or what makes memory volatile versus not volatile

Name two examples of input devices.

• keyboard

• Mouse

Name two output devices

• speakers

• Printers

have to name the binary digits used by the computer.

0 and 1

Two examples of application software

• Word

• Google Sheets

I will give you a matrix size and a bit depth, and you have to tell me what the size of the image file would be

you take your matrix size, multiply that together, because that tells you how many pixels are in that matrix. And you multiply it times, the bit depth, divided by eight.

I'm gonna give you a big old number in byte that you have to turn into megabytes

to do that, you have to divide it by 1024. 
That would give you kilobytes. And then if you divide it by 1,024, again, that would give you megabytes.