a 3d-printing based learning - lamar university...4. anim8or 5. art of illusion 6. blender 7....

A 3D-printing based learning

Stefan Andrei, PhD

Associate Professor and Chair

Presentation, Lamar University, 201611/17/2016 1

Summary

Innovative ways to learn and teach

3D Printing technologies

Designing 3D artifacts for learning and teaching

Engaging students, staff, and instructors in the 3D-

printing based learning and teaching at Lamar

University

11/17/2016 Presentation, Lamar University, 2016 2

Innovative ways to learn and teach The collaborative way of learning, where children sit around a

table to work out a problem together

(http://www.bbcactive.com/BBCActiveIdeasandResources/Innov

ativeteachingmethodsvsthetraditionaluni.aspx).

The use of educational video during lectures, which has

transformed the engagement levels of students and has created

a greatly enhanced learning experience

(http://www.bbcactivevideoforlearning.com/).

Tom Drummond, University of North Carolina at Charlotte,

compiled a list of 12 best practices for learning and teaching

concepts (http://teaching.uncc.edu/learning-resources/articles-

books/best-practice/instructional-methods/best-practices-

summary)


http://www.bbcactive.com/BBCActiveIdeasandResources/Innovativeteachingmethodsvsthetraditionaluni.aspx

http://www.bbcactivevideoforlearning.com/

http://teaching.uncc.edu/learning-resources/articles-books/best-practice/instructional-methods/best-practices-summary

Drummond’s 12 best practices1. Lecture Practices: effective ways to present new information

orally to fit differences in learning styles.

interaction with audience, questions, surveys, explanations, stories

2. Group Discussion Triggers: effective ways to present a

common experience to engage a group in a discussion.

short readings, individual task review, case studies

3. Thoughtful Questions: effective ways to formulate questions

that foster engagement and confidence.

descriptions, reflections, analogies, predictions, justifications

4. Reflective Responses to Learner Contributions: effective

ways to establish mutually beneficial communication by

reflective listening.

paraphrase, parallel personal comment


Drummond’s 12 best practices (cont’d)5. Rewarding Learner Participation: effective ways to support

learner actions with well-timed, encouraging positives.

avoid praise, description, narration, self-talk

6. Active Learning Strategies: effective ways to foster active,

constructive participation.

construction spirals, rounds, brainstorm, writing in class, concept

models, simulations/games, peer teaching, question pairs, examinations

7. Cooperative Group Assignments: ways to assign formal

cooperative tasks.

5. team member teaching, team effectiveness design, poster sessions

8. Goals to Grades Connections: establish a logical agreement of

goals and objectives, flowing to measures of performance,

criteria, and grading.

grades are referenced to criteria, requirements are detailed in writing


Drummond’s 12 best practices (cont’d)9. Modeling: represent openness, continuous learning, and trust.

openness to experience in the here and now, incorporation into oneself

of the process of change

10. Double Loop Feedback: facilitating mutual awareness of how

one learns to learn.

objective description of physical reality, culturally accepted meaning,

judgments and personal reality

11. Climate Setting: regulate the physical and mental climate.

meet the learner's needs for physical comfort and accessibility, define

negotiable and non-negotiable areas, clarify the instructor's role, and the

learner's role as members of a learning community

12. Fostering Learner Self-Responsibility: allow learners to plan

and evaluate much of their learning.

involve learners in mutual planning, involve learners in formulating their

learning objectives11/17/2016 Presentation, Lamar University, 2016 6

https://www.sculpteo.com/blog/2015/11/17/3d-

printing-in-education-from-elearning-to-emaking/

Learning by making has a long established story in education,

and thanks to 3D Printing this educational principle makes a real

come-back (November, 2015).

Introducing 3D Printing into classrooms changes both the way

students learn and the way educators teach.

Every professor using a 3D printer in the classroom or using a

cloud 3D Printing Service has observed:

3D Printing is changing the relationship between students and teachers.

First because 3D Printing technology is new and evolving constantly in

many manners.

There are a limited amount of experts in 3D Printing around the world and

it’s difficult to be aware of every application of 3D printing that takes place.

3D Printing classes are more open to discussion and student contributions

are an important factor of success.


https://www.sculpteo.com/blog/2015/11/17/3d-printing-in-education-from-elearning-to-emaking/

Main idea of Additive Manufacturing

Additive Manufacturing (AM) is a term to describe a set of

technologies that create 3D objects by adding layer-upon-

layer of material, which can vary from technology to

technology, e.g.:

plastic, liquid, metal, powder filaments, sheet of paper, etc.

But the common feature for all Addictive Manufacturing is the:

usage of a computer together with a special 3D modeling software.

So, first thing to start:

create a CAD sketch.

Then:

AM device reads data from CAD file and builds a structure layer by

layer from printing material.


Examples of 3D printers: http://3dprintingfromscratch.com/common/types-

of-3d-printers-or-3d-printing-technologies-overview/


http://3dprintingfromscratch.com/common/types-of-3d-printers-or-3d-printing-technologies-overview/

Types of input files1. Standard Tessellation Language (STL) file.

2. Virtual Reality Modeling Language (VRML), a newer digital 3D file

type that also includes color.

3. Additive Manufacturing File Format (.AMF) is a new XML-based

open standard for 3D printing.

4. GCode - this file contains detailed instructions for a 3D printer to

follow for each slice, such as the starting point for each layer and

the "route" that the nozzle or print head will follow in laying down

the material.

5. In addition, 3D printer manufacturers may have their own

proprietary input file formats that contain instructions specific to

the methodology for that make or model, and that are compatible

only with that manufacturer's software.

Note. This does not create a barrier to printing with these machines, as the

proprietary file format is generated from the user's own STL or VRML file.


Free 3D software

1. Google SketchUp

2. 3DCrafter

3. 3Dtin

4. Anim8or

5. Art of Illusion

6. Blender

7. BRL-CAD

8. Creo Elements/Direct - formerly

CoCreate

9. DrawPlus Starter Edition


10. Wings 3D

11. FreeCAD

12. GLC Player

13. LeoCAD

14. Netfabb Studio Basic

15. K-3D

16. OpenSCAD

17. Tinkercad

3DS Max - High-end commercial 3D

modeling tools

1. Alibre - One of the most

affordable CAM programs.

2. AC3D

3. AutoCAD

4. AutoQ3D

5. Cheetah3D

6. Cloud9

7. FormZ


8. Maya

9. Magics

10. NetFabb

11. Rhino3D

12. Solidworks

13. ZBrush

Free STL software:

1. MeshLab:

Open source software for processing and editing of unstructured 3D

triangular meshes.

It also has an extremely fast slide function.

2. Google SketchUp plugin:

A plugin script to import and export STL files for Google SketchUp.

Supports both binary and ASCII import and export.

3. STL-viewer:

Display and manipulate the contents of stereolithography or STL file.

4. Netfabb Studio:

A free Windows program for 3D printing to view, edit, analyze and

repair STL files.


Google: context free grammar for

"standard tessellation language" (STL)


The STL file structure (byte code – 7MB)


The STL file structure (text file – 1.3 MB)


The STL file structure (snippet of text

representation)


solid OpenSCAD_Model

facet normal 0 0 0

outer loop

vertex -12.892 -0.886857 15.3505

vertex -12.8413 -1.22597 15.1614

vertex -13.2 -1.22597 15.1142

endloop

endfacet

. . .

endsolid OpenSCAD_Model

The STL file structure (similar to reverse

engineering) The following Context-Free Grammar can generate the previous

text (Open-Source Computer Assisted Design model):

1. S → solid OpenSCAD_Model Facets endsolid OpenSCAD_Model

2. Facets → Facet Facets | Facet

3. Facet → facet Position Origine OuterLoop endfacet

4. Position → normal | orthogonal

5. Origine → X_origine Y_origine Z_origine

6. X_origine → Number

7. Y_origine → Number

8. Z_origine → Number

9. OuterLoop → Vertex_A Vertex_B Vertex_C

. . .


The STL file structure (reverse engineering)

. . .

10. Vertex_A → vertex A_coord B_coord C_coord

11. Vertex_B → vertex A_coord B_coord C_coord

12. Vertex_C → vertex A_coord B_coord C_coord

13. A_coord → Number

14. B_coord → Number

15. C_coord → Number

16. Number → IntegerPart . FractionalPart

17. IntegerPart → Digit | IntegerPart Digit

18. FractionalPart → Digit | Digit FractionalPart

19. Digit → 0 | 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9


Is reverse engineering legal?

In the U.S., Section 103(f) of the Digital Millennium

Copyright Act (DMCA) (17 USC § 1201 (f) - Reverse

Engineering) specifically states that it is legal to

reverse engineer and circumvent the protection to

achieve interoperability between computer programs

(such as information transfer between applications).

Interoperability is defined in paragraph 4 of Section

103(f).


Popular 3D printers technologies

1. Stereolithography (SLA)

2. Fused Deposition Modeling (FDM)

3. Selective Laser Sintering (SLS)

4. Selective Laser Melting (SLM)

5. Electronic Beam Melting (EBM)

6. Laminated Object Manufacturing (LOM)

7. Bio Printers (recent technology)


1. Stereolithography (SLA)

This method was patented by Charles Hull, co-founder of

3D Systems, Inc., in 1986.

He then set up 3D Systems Inc to commercialize his patent

(www.3Dsystems.com).

In fact, Japanese researcher Dr. Hideo Kodama first (1981)

invented the modern layered approach to stereolithography

by using ultraviolet light to cure photosensitive polymers.

The process of printing involves a uniquely designed 3D

printing machine called a stereolithograph apparatus (SLA),

which converts liquid plastic into a solid 3D object

(represented as a computer aid design (CAD) file, such as

STL).


http://www.3dsystems.com/

The SLA machine and its 3D

generated object


2. Fused deposition modeling (FDM) Fused deposition modeling (FDM) technology was developed and

implemented at first time by Scott Crump, Stratasys Ltd. founder, in

1987.

Other 3D printing companies have adopted similar technologies but

under different names.

A well-known nowadays company MakerBot coined a nearly

identical technology known as Fused Filament Fabrication (FFF).

With the help of FDM you can print not only functional prototypes,

but also concept models and final end-use products (resolution

1/20 per mm).

high-performance and engineering-grade thermoplastic,

very beneficial for mechanic engineers and manufactures.

the only 3D printing technology that builds parts with production-grade

thermoplastics,

excellent mechanical, thermal and chemical qualities.


Similarity with SLA printing method

3D printing machines that use FDM Technology

build objects layer by layer from the very bottom up

by heating and extruding thermoplastic filament.

FDM is a bit similar to stereolithography (SLA).

Comparing to stereolithography, this technique is

slower in processing, but with better resolution.

When printing is completed, support materials can

easily be removed either by placing an object into a

water and detergent solution or snapping the support

material off by hand.


Examples of FDM 3D-printed objects


Benefits to the society FDM technology is widely spread nowadays in variety of

industries such as:

automobile companies like Hyundai and BMW or

food companies like Nestle and Dial.

end-use products, particularly small, detailed parts and specialized

manufacturing tools.

food, drug packaging, and the medical industry.

FDM is used for new product development, model concept

and prototyping and even in manufacturing development.

The most common filaments are:

ABS (acrylonitrile butadiene styrene),

PC (polycarbonate) filaments,

PLA (polylactic acid) made out of corn.


Price ranges

The price for those 3D printers depends on size and

model.

Professional ones usually cost from $10,000 and more.

3D Printers designed for home use are not so expensive.

There are several models like Replicator of MakerBot,

Mojo of Stratasys and Cube of 3D Systems.

The price for these models varies from $1,200 to $10,000.

However, new start-ups offer more and more affordable

versions of FDM 3D printers, the price of which can be just

about $300-$400.


3. Selective Laser Sintering (SLS)

… is a technique that uses laser as power source to form

solid 3D objects.

This technique was developed by Carl Deckard, a student

of Texas University, and his professor Joe Beaman in

1988.

Later on they took part in foundation of Desk Top

Manufacturing (DTM) Corp., that was sold to its big

competitor 3D Systems in 2001.

The main difference between SLS and SLA is that it uses

powdered material in the vat instead of liquid resin as

stereolithography does.


Comparison with SLA and FDM

Unlike some other additive manufacturing processes,

such as stereolithography (SLA) and fused deposition modeling (FDM),

SLS does not need to use any support structures as the

object being printed is constantly surrounded by unsintered

powder.


Example of an SLS 3D printed object


Materials and prices used by SLS

Like all other methods listed above the process starts with

creation of computer-aided design (CAD) file, which then needs to be converted to .stl format by special software.

The material to print with might be anything from nylon,

ceramics and glass to some metals like aluminum, steel or

silver.

Due to wide variety of materials that can be used with this

type of 3D printer the SLS technology is very popular for 3D

printing customized products.

SLS is more spread among manufactures rather than 3D

amateurs at home as this technology requires the use of high-

powered lasers, which makes the printer to be very

expensive.


4. Selective laser melting (SLM)

… is a technique that also uses 3D CAD data as a source

and forms 3D object by means of a high-power laser

beam that fuses and melts metallic powders together.

In many sources SLM is considered to be a subcategory

of selective laser sintering (SLS).

But this is not so true as SLM process fully melts the

metal material into solid 3D-dimentional part unlike

selective laser sintering.

The history of SLM started with German research project

held by group of Fraunhofer-Institut für LaserTechnik in

1995.


The main design of SLM


Example of an SLM 3D printing object


The main idea of SLM printing

The fine metal powder is evenly distributed onto a plate,

then each slice of 2D layer image is intensively fused by

applying high laser energy that is directed to the

powdered plate.

The energy of laser is so intense that metal powder

melts fully and forms a solid object.

After the layer is completed the process starts over again

for the next layer.

Metals that can be used for SLM include stainless steel,

titanium, cobalt chrome and aluminum.


Applications

1. parts with complex geometries and structures with thin walls

and hidden voids or channels.

2. aerospace application for different lightweight parts.

3. tooling and physical access difficulties to surfaces for

machining, as well as restrict the design of components.

4. manufactures of aerospace and medical orthopedics.


5. Electronic Beam Melting (EBM)

EBM is another type of additive manufacturing for metal

parts.

It was originally coined by Arcam AB Inc. in 2001.

The same as SLM, this 3D printing method is a powder

bed fusion technique.

While SLM uses high-power laser beam as its power

source, EBM uses an electron beam instead, which is

the main difference between these two methods.

The rest of the processes is pretty similar.


The main idea of EBM 3D printing

The material used in EBM is metal powder that melts

and forms a 3D part layer by layer by means of a

computer, that controls electron beam in high vacuum.

Contrary to SLS, EBM goes for full melting of the metal

powder.

The process is usually conducted under high

temperature up to 1000 °C.


Prices and applications

Comparing to SLM the process of EBM is rather slow

and expensive, also the availability of materials is

limited.

So the method is not so popular though still used in

some of manufacturing processes.

Currently the most well spread materials that are used

for EBM are commercially pure Titanium, Inconel 718

and Inconel 625.

The application of EBM is mainly focused on medical

implants and aerospace area.


6. Laminated object manufacturing (LOM)

… is one more rapid prototyping system that was

developed by the California-based company Helisys Inc.

in 2013.

During the LOM process, layers of adhesive-coated

paper, plastic or metal laminates are fused together

using heat and pressure and then cut to shape with a

computer controlled laser or knife.

Post-processing of 3D printed parts includes such steps

as machining and drilling.


The main steps of LOM 3D printing

The LOM process includes several steps.

Firstly, CAD file is transformed to computer format, which

are usually STL or 3DS.

LOM printers use continuous sheet coated with an

adhesive, which is laid down across substrate with a

heated roller.

The heated roller that is passed over the material sheet

on substrate melts its adhesive.

Then laser or knife traces desired dimensions of the part.

Also the laser crosses hatches of any excess material in

order to help to remove it easily after the printing is done.


Prices and speed of LOM

Probably LOM is not the most popular 3D printing

method but one of the most affordable and fastest.

The cost of printing is low due to not expensive raw

materials.

Objects printed with LOM can be relatively big, that

means that no chemical reaction needed to print large

parts.


A LOM 3D printed object


LOM Vendors

Currently Cubic Technologies, the successor to Helisys

Inc., is the main manufacturer of LOM printers.

There are not too many companies these days that work

with LOM technology.

Additional vendor: the Irish company Mcor Technologies

Ltd. sells LOM 3D printers.

Their devices are widely being used by artists, architects and

product developers to create affordable projects from usual letter

paper.

The printers that are being sold by Cubic Technologies for

home use are pretty expensive comparing to Makerbot

Replicator or 3D System’s Cube devices.


7. BioPrinting … is the process of creating cell patterns in a confined space

using 3D printing technologies.

Applications:

to print tissues and organs to help research drugs and pills

to incorporate the printing of scaffolds for regenerating joints and

ligaments

Organovo (San Diego, 2007): designs and develops functional,

three dimensional human tissue with NovoGen MMX Bioprinter

(www.organovo.com)

The living test tissues provide researchers the opportunity to test drugs

before administering the drug to a living person.

Inkredible (Sweden, 2015): the first true bench-top 3D bioprinter

with Clean Chamber Technology (http://www.cellink3d.com/)

With a HEPA filtered positive air pressure inside the printing chamber, it is

sure that the bioprinting is sterile.


http://www.organovo.com/

http://www.cellink3d.com/

LU: Recent acquisitions

We recently acquired a MakerBot Desktop 3D Printer

which uses PLA material to be extruded into layers.

We also recently acquired an Inkredible printer.

We have also designed, implement, and test two DIY 3D

printers: Ultimaker and PrntBot

http://galaxy.lamar.edu/~sandrei/Ultimaker/index.html


http://galaxy.lamar.edu/~sandrei/Ultimaker/index.html

Makerbot

Replicator Z18


College of Arts and Sciences’ Facebook


Example … of an innovative and unique way for content, mode of

delivery and pedagogy of teaching courses using 3D printed

artifacts.

To the best of our knowledge, all ‘Foundations in Computer

Science’ courses are currently taught like this:

A pushdown automata is a 7-tuple M = (Q, , , q0, Z0, A, ), where Q is a

finite set of states, the input and stack alphabets and are finite sets, q0

Q is the initial state, Z0 is the initial stack symbol, A Q is the set of

accepting states, and the transition function is : Q ( {}) the

set of finite subsets of Q *.

A configuration of a PDA is a triple (q, x, ), where q Q is the current

state, x * is the portion of the input string that has not yet been read, the

contents of the stack is *.

According to the student evaluations and other sources, most of students

struggle to understand this complicated concept (and the configuration

transitions).


Our approach is 3D-model oriented…

The below photos show a group of students explaining the concept

of pushdown automata with the help of a physical 3D printed artifact,

the behavior of a pushdown automata becomes crystal clear (COSC

3302 – Introduction to Computer Theory) – Mr. Tim Gonzales


Student assessment about this concept

While the definition of the pushdown automata looked

complicated, once they’ve seen the 3D printed artifact,

the students have now a very clear understanding and

using the concept of pushdown automata.



Case Study: COSC 5328 Real Time Systems

A game board for Example of slide 5

The below figure shows the scheduling game board representation of this task set at time i = 0.

The x-axis shows the laxity of a task and the y-axis shows its remaining computation time.


Scheduling single-instance tasks with

game board Let C(i) denote the remaining computation time of a

task at time i, and let L(i) denote the laxity (slack) of a task at time i (i.e., L(i)=D(i)-C(i)-S(i)).

On the L-C plane of the scheduling board, executing any n of the m tasks in parallel corresponds to moving at most n of the m tokens one division (time unit) downward and parallel to the C-axis.

Thus, for tasks executed: L(i+1) = L(i), C(i+1)=C(i)-1

Tokens corresponding to the remaining tasks that are not executed move to the left toward the C-axis.

Thus, for tasks not executed: L(i+1) = L(i)-1, C(i+1)=C(i)


Rules for the Scheduling Game Board

Each configuration of tokens on the L-C plane represents the scheduling problem at a point in time.

The rules for the scheduling game are: Initially, the starting L-C plane configuration with tokens

representing the tasks to be scheduled is given.

At each step of the game, the scheduler can move at most ntokens one division downward toward the horizontal axis.

The rest of the tokens move leftward toward the vertical axis.

Any token reaching the horizontal axis can be ignored (it has completed its execution).

The scheduler fails if any token crosses the vertical axis into the second quadrant before reaching the horizontal axis.

The scheduler wins if no failure occurs.


EDF scheduler fails (ex. From slide 5)

Example of two-processor system (n = 2) for three

single-instance non-preemptive tasks:

J1: S1 = 0, c1 = 1, D1 = 2

J2: S2 = 0, c2 = 2, D2 = 3

J3: S3 = 0, c3 = 4, D3 = 4

J1 and J2 have earlier absolute deadline, so they are

assigned to start.


LL scheduler wins (ex. From slide 5)

Their laxities are l1 = 1, l2 = 1, and l3 = 0.

At time 0, J3 has the lowest laxity, so it is assigned to start.

The other one can be J1 (since it has same laxity as J2).

LLF is not optimal Example of two-processor system (n = 2) for six single-instance

non-preemptive tasks:

J1: S1 = 0, c1 = 2, D1 = 2

J2: S2 = 0, c2 = 2, D2 = 2

J3: S3 = 0, c3 = 3, D3 = 6

J4: S4 = 0, c4 = 3, D4 = 6

J5: S5 = 0, c5 = 1, D5 = 5

J6: S6 = 0, c6 = 1, D6 = 5

Their laxities are sorted increasingly: l1 = 0, l2 = 0, l3 = 3, l4 = 3, l5 = 4, l6 = 4.

This is because tasks J1 and J2 will be chosen to be first executed on

processors 1 and 2, respectively.

Then, J3 and J4 will be scheduled for processors 1 and 2, but tasks J5 and

J6 cannot be scheduled because they will miss their deadline of 5.


However, EDF is optimal for previous

example

We re-arrange the jobs according to earliest

deadline first strategy:

J1, J2, J5, J6 ,J3 and J4

This arrangement will lead to a feasible

schedule.


EDF and LLF are not optimal for

multiprocessor non-preemptive case Three-processor system (n = 3) for seven single-instance non-

preemptive tasks:

J1: S1 = 0, c1 = 2, D1 = 2

J2: S2 = 0, c2 = 7, D2 = 7

J3: S3 = 0, c3 = 8, D3 = 9

J4: S4 = 0, c4 = 3, D4 = 6

J5: S5 = 0, c5 = 1, D5 = 5

J6: S6 = 0, c6 = 5, D6 = 12

J7: S7 = 0, c7 = 3, D7 = 11

Their laxities are: l1 = 0, l2 = 0, l3 = 1, l4 = 3, l5 = 4, l6 = 7, and l7 = 8.

LLF assigns J1, J2, and J3 to processors 1, 2, and 3, respectively.

Then J4 is executed by processor 1.

Hence, J5 will miss its deadline.


EDF and LLF do not work for previous

example, but there is a feasible schedule!

EDF assigns J1, J5, and J4 to processors 1, 2, and 3,

respectively.

Hence, J2 will miss its deadline.

But … is the previous task set feasible?

Actually, it is … the feasible schedule is:

First, J1, J2, and J3 to processors 1, 2, and 3, respectively.

Then, J5, J6, and J7 are executed by processors 1, 2, and 3.

Finally, J4 is executed by processor 1.



Causal Order in the Declarative Model

In a concurrent program all execution states

of a given thread are totally ordered.

The execution state of the concurrent

program is partially ordered.

computation step

thread T1

thread T2

thread T3

fork a thread

3D model for teaching the scheduling

problem for multiprocessor platform


Example of two-processor system (n=2) for three single-instance tasks:

J1: S1 = 0, c1 = 1, D1 = 2J2: S2 = 0, c2 = 2, D2 = 3J3: S3 = 0, c3 = 4, D3 = 4


Case Study: COSC 3308 Programming Languages Concepts

Causal Order in the Declarative Model

computation step

thread T1

thread T2

thread T3

fork a thread

bind a dataflow variable

synchonize on a dataflow variable

x

y


Nondeterminism

An execution is nondeterministic if there is a

computation step in which there is a choice

what to do next.

Nondeterminism appears naturally when

there are multiple concurrent states.

3D model for teaching the ‘fork and

join’ concept


In parallel computing, the fork–join

model is a way of setting up and

executing parallel programs, such

that execution branches off in

parallel at designated points in the

program, to "join" (merge) at a

subsequent point and resume

sequential execution.

Bucket Sort and Radix Sort

(COSC 2336 – Data Structures)

All sort algorithms discussed so far are general

sorting algorithms that work for any types of keys

(e.g., integers, strings, and any comparable objects).

These algorithms sort the elements by comparing

their keys.

The lower bound for general sorting algorithms is

O(n · log n).

So, no sorting algorithms based on comparisons

can perform better than O(n · log n).

However, if the keys are small integers, you can

use bucket sort without having to compare the keys.

11/17/2016 68COSC-2336, Lecture 6

Bucket Sort and Radix Sort (cont)

Bucket sort, or bin sort, is a sorting algorithm that works

by partitioning an array into a number of buckets.

Each bucket is then sorted individually, either using a

different sorting algorithm, or by recursively applying the

bucket sorting algorithm.

It is a distribution sort, and is a “cousin” of radix sort in

the most to least significant digit manner.

Since bucket sort is not a comparison sort, the Ω(n · log

n) lower bound is not applicable.

The computational complexity estimates involve only the

number of buckets.

11/17/2016 COSC-2336, Lecture 6 69

Bucket Sort The bucket sort algorithm works as follows.

Assume the keys are in the range from 0 to N-1.

We need N buckets labeled 0, 1, ..., and N-1.

If an element’s key is i, the element is put into the bucket i.

Each bucket holds the elements with the same key value.

Given n the number of integers, the worst-case time

complexity of the bucket sort algorithm is O(n).

More precisely, it is n · N · D, where D is the maximum

number of digits of the given integers. You can use an ArrayList or a Bag to implement a bucket.

bucket[0]

Elements

with key 0

bucket[1]

Elements

with key 1

bucket[2]

Elements

with key 2

…

bucket[N-1]

Elements

with key N-1

11/17/2016 70COSC-2336, Lecture 6

Bucket Sort (cont)

Sort 331, 454, 230, 34, 343, 45, 59, 453, 345, 231, 9

230

bucket[0]

331

231

bucket[1]

bucket[2]

343 453

bucket[3]

454

34

bucket[4]

45

345

bucket[5]

bucket[6]

bucket[7]

bucket[8]

59

9

bucket[9]

230, 331, 231, 343, 453, 454, 34, 45, 345, 59, 9

9

bucket[0]

bucket[1]

bucket[2]

230

331

231 34

bucket[3]

343 45

345

bucket[4]

453 454

59

bucket[5]

bucket[6]

bucket[7]

bucket[8]

bucket[9]

9, 230, 331, 231, 34, 343, 45, 345, 453, 454, 59 9

34

45

59

bucket[0]

bucket[1]

230 231

bucket[2]

331

343

345

buckets[3]

453 454

buckets[4]

bucket[5]

bucket[6]

bucket[7]

bucket[8]

bucket[9]

9, 34, 45, 59, 230, 231, 331, 343, 345, 453, 454

11/17/2016 71COSC-2336, Lecture 6

The 3D-printed artifact for bucket sort


3D LU logo approval


LU logo, LU nut and bolt, and the

mechanical clock


Methyl methacrylate (C5H8O2 )


A medical weekly planner


Photos taken by Ms. Paula Gregory


LU cup, cell-phone holder, LU avatar


Inkredible 3D printer The creators of the INKREDIBLE started their company with

CELLINK, a bioink that has become the most widely used bioink in

the world thanks to its excellent biocompatibility, printability, and

structure that ensures 98% cell viability (study made with RoosterBio

cells at Chalmers University in Sweden) – September 2015.

Another great feature of the INKREDIBLE is its clean chamber

technology.

The printer has a highly filtered air flow with positive pressure

created inside the chamber so it reduces contamination and particle

count inside the printing area basically down to zero.

The bioprinting services that CELLINK provides has been a great

success for many partners and the fact that these partners can

receive cell specific expertise enables for new proprietary tissue

model creation for internal product development testing platforms.


The newly optimized desktop bioprinter for the

ultimate bioprinting of human tissues and 3D cell

culturing


Our INKREDIBLE at LU (calibrating and

then printing a human ear) – Mr. Greg Yera


Less than 4%

universities

worldwide

purchased

BioInkredible.

Wollongong

University in

Australia and

Leading schools

in South Korea

and

Switzerland.

Assembling the Ultimaker 3D printer and

designing 3D-printed artifacts (Mr. Vraj Pandya)


https://3dprint.com/19305/biobots-3d-

bioprinter/


https://3dprint.com/19305/biobots-3d-bioprinter/

The V. W. Keck Printing Center at UTEP


Future of 3D printing

Richard D’Aveni, The 3-D Printing Revolution. 3-D Printing Will

Change the World, Harvard Business Review-Innovation, May

2015, [available online at https://hbr.org/2015/05/the-3-d-printing-

revolution]

Industrial 3-D printing is at a tipping point, about to go mainstream in a

big way. Most executives and many engineers don’t realize it, but this

technology has moved well beyond prototyping, rapid tooling, trinkets,

and toys.

“Additive manufacturing” is creating durable and safe products for sale to

real customers in moderate to large quantities.

It may be hard to imagine that this technology will displace today’s

standard ways of making things in large quantities. Traditional injection-

molding presses, for example, can spit out thousands of widgets an hour.


https://hbr.org/2015/05/the-3-d-printing-revolution

Our plan at LU on 3D printing


Engaging students, staff, and instructors in the

3D-printing based learning and teaching at LU1. Think for an initial idea of a 3D model with the functionality

described in lecture notes

2. Check the existing databases of 3D models

3. While (prototype needs changes) {

1. Design the 3D software model (e.g., Blender)

2. Print a 3D model, a.k.a., prototype (e.g., Makerbot)

3. Test the prototype, ask feedback from students/colleagues/

collaborators

4. }

5. Collaborate with other departments/universities/institutions

6. Create a database with STL 3D files published under the

Creative Commons License


Thank you for your attention!

Questions?

Presentation, Lamar University, 201611/17/2016 88

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