Author: Wendy Wei

  • Artificial Intelligence

     

    According to ‘Wikipedia’, Artificial Intelligence (AI) is defined as the study of ‘intelligent agents’. AI can replace the human identification, recognition, analysis, decision-making and other functions. When you say a word, the machine can recognize the words, and understand the meaning of your words. AI has a history of 61 years first starting from the Dartmouth meeting (the longest continuous bilateral dialogue between American and Soviet representatives) in 1956. During the historical development of AI, there are obvious ups and downs. At least, we have been through two ‘winters’ of AI. Allen Newell and his students win the game checkers, solving word problems in algebra and prove logical theorems. However, later they found that they fail to recognize the difficulty of some remaining tasks. Luckily, according to researchers, we have reached the ‘gold age of Artificial Intelligence nowadays.

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    Artificial Intelligence has broken the records in multiple fields. In 2016, the latest version of voice-identifier developed by Microsoft lab has reached an error rate of 5.9%. This is the first time when artificial intelligence has the same voice identifying error rate as that of a human being. In the image identifier competition-ImageNet, which uses computers to identify the 1000 kinds of images, ResNet from Microsoft won the championship with an error rate of 3.5% (compare to 5.1% – the error rate of image identifier of a human being).( https://en.wikipedia.org/wiki/Artificial_intelligence#History)

    屏幕快照 2017-11-17 下午1.04.12

    Besides voice and image, artificial intelligence has a huge improvement in natural language. The new function of Microsoft translator published in December 2016 supports over 50 languages and can achieve simultaneously translates multiple languages spoken or written by different people. In the future, people may encounter others from different countries, but as soon as we use this app, we could hear our mother language.

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    Voice, image, and language applications are practical. Recently, artificial intelligence has some huge breakthroughs in fields that are complex. We can even use artificial intelligence to play video games. Artificial intelligence has found the quickest ways to get scores in 120 minutes. If we keep training this robot, it will reach the master level of the game in 240 minutes and successfully finds the tricks we cannot find ourselves while playing the game.

    (https://www.theverge.com/2015/2/25/8108399/google-ai-deepmind-video-games)

    AlphaGo uses a huge amount of data to the self-play process. After a long time of training, it beats the world champion in chess Shishi Li with a score of 4:1. Since it uses self-play process, as long as given enough time and examples, it never stops training itself.( https://qz.com/502325/an-ai-computer-learned-how-to-beat-almost-anyone-at-chess-in-72-hours/) That is why it won masters in chess 60 rounds continuously.

    All those new developments in artificial intelligence field make it popular among people from all over the world. However, if we abandon the superficial thoughts we have for artificial intelligence and think deeply of its structure, it is not hard to find the basic problems that are unsolved hidden in artificial intelligence field. This requires all of us who are deeply interested in artificial intelligence to be calm and think about the future development of artificial intelligence.

    Nowadays, artificial intelligence can roughly be separated into two parts: deep learning and reinforcement learning. Deep learning uses a very complicated model to imitate the imports and outputs. Reinforcement learning is deciding the best solution through the interaction between learning machine and environment. The reason behind the huge success of deep learning as well as reinforcement learning is that all the models are trained by large databases. However, what if the areas do not have a lot of databases for AI machines to test themselves?

    The fact that artificial intelligence needs a lot of databases to train an effective model instead of learning from scratch is a hidden danger in artificial intelligence. Now we are living in the big data world. For images, we can train the models by thousands of images. For voices, there is a huge number of voice data that we can use for training AI. For translators, we can use language samples to train the models. These databases make deep learning possible. However, this is certainly not the perfect solution for all fields. In many areas, it is hard or even impossible to get a similar database. For instance, some rare diseases in the medical field have only a few examples throughout the world. Only if we find the way to overcome the need for big data, can we enable the breakthrough in artificial intelligence technology and broaden the area of it.

    The second challenge is about the size of the model and the difficulty of training the models. The internet used for training artificial intelligence always has a large coefficient as of billions.

    Facing such a network, there are at least two difficulties: one is that we often refer to the gradient abatement and gradient explosion problems.

    This phenomenon described in above steps is what we know as “vanishing gradient problem”.Trying the same approach as mentioned above, but when the observations are totally opposite, it tends to be “exploding gradient problem”.( https://medium.com/@sayondutta/intelligent-signals-unstable-deep-learning-why-and-how-to-solve-them-295dc12a7fb0)

    When the deep network has many levels, the output layer and the label between the calculated residual or Loss function are difficult to effectively pass to the bottom. So, in the use of this reverse communication training, the underlying network parameters are usually not very easy to be defined as effective training. They usually have poor performances.

    The high coefficient means the storage of the model is so large that it exceeds the storage of a GPU card. Therefore, separate computing and parallel models are required. However, it is time-consuming to get the models.

     

    As artificial intelligence is getting increasingly successful in many fields, some people may be concerned that in the future AI may take over the jobs of human beings. However, in my consideration, AI and the work of human being are complementary to each other. Agents are fast, rigorous, precise, explicit and objective. However, they lack common sense and the ability to deal with novel situations. On the other hand, common sense is just the strength of us human beings. Therefore, I believe with the help of AI, more challenges with the rapid development of technology could be solved toward the knowledge economies.

     

    Reference:

    (1)Tecuci, G Artificial Intelligence March 2012, Vol.4(2), pp.168-180

    (2)Tecuci, Gheorghe.Building Intelligent Agents: an apprenticeship multistrategy learning theory, methodology, tool and case studies. Academic Press , 1998

     

     

     

     

     

     

     

     

  • 3-D printing

    In my childhood, I always imagined the picture of me talking to myself. As I grow up, I first saw the introduction of 3-D printing on TV. 3-D printing makes me believe the possibility of creating another me.

    3-D printing also called Additive Manufacturing(AM) refers to any process of printing 3-dimensional objects. Under the control of a computer, the raw material is piled on top of another.

    To better understand the principle of 3-D printing, let’s first focus on the traditional way of printing—2-D printing. Traditional printing works on the pictures on a plane. Digital pictures consist of pixel plots with pure colors. It can be seen as every coordinate plot stores one color. Transmission is completed by synchronous orbits.

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    Instead of paper and paintings, the raw material for 3-D printing is normally thermal plastic which turns soft when heated. Nowadays the most common material for 3-D printing is ABS. PLA is also called Polylactic Acid. It has a very low melting point of below 185 Celsius. Therefore, it is used broadly in 3-D printing. It appears as wire rod just like wool, so it is not easy to stuck the painter.

    Now that we know the material of 3-D printing, let’s see how the printer works. For x-axis and y-axis, we use a small steel plate on synchronous orbits. For z-axis, we use a thick rod appearing like a screw. And that is the basic construction of a 3-D printer. It is not as complicated as I originally thought. Basically, we just need to make a sprinkler head that can move in a three axis. Then, use silk thread to create planes and pile up the planes into a three-dimensional object.

    We only need a JPG formed picture to print a picture. However, what kind of form do we need to complete a 3-D printing? In industrial design and architecture, rhino and solid work are really popular software. Almost all software in the world have the same basic function—squeeze. The form of a model for 3-D printing is STL..

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    Now let’s discover the technology of 3-D printers.

    1. FDM(Fused Decomposition Modeling)

    The key to FDM is to keep the temperature 1 Celsius above the melting point of the raw material. The sprinkler head is controlled by CAD tier data to make the raw material squeezed out and solidify as thin layers. The layers pile up to form a model.

    name FDM
    material ABS,PC,PLA
    precision 0.025-0.762mm

    The principle of construction of the system and operation are very easy. Maintenance cost is low. System operates safely. It can be used in lost wax casting and forming parts of any complexity. It does not need chemical cleaning.

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    1. SLA(Stereo Lithography Apparatus)

    SLA uses photosensitive resin as raw material and scans UV laser controlled by a computer so that the scanned area of the resin layser has photopolymerization reaction and form a layer of the component. Through continuously bonding the previous layer, the whole object is created.

    name SLA
    material Photosensitive resin
    precision 0.1-0.2mm

    This method has a high degree of molding process, a high precision of sizes and great quality. It uses CAD data model to lower the cost of repairing. It can work on objects with complicated structures.

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    1. SLS(Selected Laser Sintering)

    It uses CO2 laser as energy source and powder material as raw materials. First, put a thin layer of powder on the working table; Then, the laser beam is selectively sintered under the control of the computer according to the layered outline of the part. After the layer is completed, the next layer is sintered. Next, remove all excess powder after sintering, grind and dry the other treatments. Nowadays, wax, plastic powder and metal powder are broadly used.

    name SLS
    material Nylon, ABS

    It can be used to make metal products with easy procedures. It does not need supporting structure. The utilization of material is high.

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    1. Ployjet

    Sliding back and forth along the x-axis, an ultrathin photosensitive resin is spread over the molding chamber. After each paving, the UV light bulb on the edge of the sprinkler head and immediately emits UV light to rapidly cure each layer of light-sensitive resin. After each print, the molded chassis inside the machine sinks, while the sprinkler head continues to work layer by layer until the prototype is completed.

    name Ployjet
    material Photosensitive resin polymeric material
    precision 0.1mm

    It can print 3-D model with high quality, great details and shorten the designing period. The range of choosing material is broad.

    (https://www.zhihu.com/question/20382142)

    Nowadays, 3-D printing has got some breakthroughs in many areas. Cornell creating machine lab states that Hydrocolloid Printing’s 3-D printing can custom food production. It is possible to print candy, chocolate and pasta now. Industrial 3D printers have existed since the early 1980s and have widely used for research purposes. Fashion designers also use the 3D printed bikini swimmer, shoed and dresses for generating ideas. Nike took advantage of 3-D printing technology in the modeling and production of Vapor Laser designed for American Players in 2012. 3-D printing has also been used in production of transplant organs, equipment and other medical fields. There are currently successful cases of a titanium pelvis transplanted by a British patient and a titanium mandibular transplanted by a Belgian patient.

    ( https://zh.wikipedia.org/wiki.E5.B7.A5.E4.B8.9A.E7.94.A8.E9.80.94)

     

    Resources:

    3D Printing.J.Maslin-Research Assoc.Dec-1976

    3D Printing: the Ultimate guide to understanding and mastering 3d printing for life.Greg Norton-Createspace Independent-2015