System Overview:

I've been working day and night on this project for the past three months! No time for play indeed. But now the simulink data matches perfectly with the actuator data and the particle filter algorithm works! Next mission is to finish my master's degree thesis and wait, just wait...

Take a glance of the sensor signal acquisition board (Click it to see the full image). You may see the EMA on the topleft, and the acclerometer sensor (it's on the left of the picture, in the middle). Acclerometer sensor is temporarily not functional so I have to detach it from the actuator.

Below is the fault diagnosis and prognosis result (The turn-to-turn winding fault is detected and the actuator's remaining useful life--RUL is calculated and shown).

There is still a slight imperfection: I calculated the PDFs (Probability Density Function) according to the particles in PF algorithm, and tried to show them in a TeeChart Winform control. However, this control seemed very ugly because former PDFs are partially shadowed by newer PDFs. There must be a better way of showing them with something else.

You may find some of my projects in the "Mobile Development" section. Some projects on WQX (An electronic dictionary with a 8-bit 6502 CPU inside) are collected specially in the "WQX Memorial" section because those memories are very precious to me.

Pleasant Visual Design

With many years' experience in game developing, I believed that an outstanding game artist contributes almost as much as the programmer or game designer.

We take huge efforts to enrich our game with the best art. In fact we have to give our game its own aesthetic style, and make everyone feel like to give it a try when they see the game at the first time.

Take 'Dudu' as example:

At first there was nothing in dudu's red head/body, Our game art (Ms.Liu) then added a trident hair onto dudu's head, making him like a pepper. During the game developing, I proposed several changes to the dudu's body, and they could be seen in the picture below:

The original dudu was in the middle, and finally we chose the dudu on the left -- the one with thin stripes. This one was more like a pumpkin:)

The result proved that many people praised our game art, especially girls:)

Lua based game architecture

I had been a Lua fan since the day I knew it. I used Lua in Infiworks, a mobile app company, and the Dudu Rush was the second commercial game I developed mainly in Lua. Three kinds of languages were used for the game:

Lua: 70%
C++: 15%
Obj-C: 15%

Mr.Zhao wrote most of the C++ and Obj-C code to do the rendering and manage the resources (in fact those codes played the role of a basic engine, I also added some C++ codes for my own conveniency), and I designed almost all the game logic in Lua.

Several years ago, I read some articles about component-based pattern. Having realized it's better than the OO pattern which always inherits, I tried to implement this pattern in my research projects, where all the codes are written in C# and I tried my best to keep my components simple and stupid. However, I did not found the great advantage of the component-based pattern until I started iPhone developing, when I mixed the static language with a dynamic one, just like Lua.

Mr.Zhao's game engine is a great example of this design pattern: Some useful components are already included in the engine: Sprite, State Machine, Action, 2D Transformation, etc. I also add a lite particle system into the engine, and control it via Lua codes (A improved version of this particle system under Windows can be found here).

Everything in the game is a mixture of multiple components, and every component is reusable at the time it is created. Extra game functions can be created through composing components together instead of inheriting from an old father class. It's clean, and it's sharp. We can prototype any gameplay we want in a few hour, and quickly adjust it when the artist designs the final character.

Unsymmetrical Jumping

In Super Mario Bros. and many other famous action games, Jumping is an common action. The character jumps over blocks or enemies to proceed in the game. Dudu rush is designed to be a "relaxed action game", that means although there are lovely characters and funny music in the game, the gameplay remains challenging. Especially, we decided that when the game character jumps, it goes up a little faster than when it goes down. Actually, the dudu goes in the air like the picture below:

This unsymmetrical jump feature also goes with air hikes. In this way, game players may experience a little tension when every jump starts, and feel relieved when they try to jump over long traps.

The only thing we never considered is the long-term goal for this game. As a free game, no bonus or upgrades is included in the original Dudu rush, The game might caught players' eye in the first glance, but few features can keep the player for a long time. so it didn't remain 1st for long in iPhone app store (in fact it stayed 1st for about two weeks, now Infiworks is developing a paid version). Anyway, the success of this game is already a surprise to me. It's really great!

This simulator runs on my android phone Meizu M9 (1GHz CPU), Radiation value are calculated on several discrete points according to Planc's law for black body radiations. I also added a trackball function: You can touch and slide the screen to rotate the whole scene!

Here is the result:

Now watch this. Can you imagine this Real Time Strategy game is running on an MTK feature phone with a CPU of only 100~150MHz and RAM of less than 300KB (Including graphical memory)?

Yes I made it! This is a really exciting RTS. AI and path finding codes are highly optimized to make the game run smoothly on very limited hardware platforms.

This game is not ready for release now, I am still looking for a good game art to cooperate with. You can get the alpha trial version below, only one tutorial map is enabled.

The game runs on IVM (Iava Virtual Machine) which is designed for millions of MTK phones in China. The IVM runtime for windows (IvcSetup.exe) is also included in the zip file:

Some more test shots:

All source code (Lua and C) can be downloaded below:

Code can be compiled with Lua 5.1 and SDL, and runs under Windows XP/Vista/7. Code::Blocks project file is also included.

PS: During my EMA-PHM project, I decided to write another script, aiming to illustrate the PF (Particle Filtering) algorithm, to render the probability of each particle, and to calculate and render the PDF (Probability Density Function) in real time. I must admit that this particle system is just for fun and I never thought of using it in my lab researches before, but now the system seems to be the perfect way of illustrating academical ideas, What a coincidence!

I hope the final work will help other students in the ATE lab, because many of them are using PF algorithm in their researches. Almost all other winform controls that I can find are way too ugly to do such a job.

The typical A-Star algorithm is not very suitable on a feature phone, because you must do with the sorting in the open and close tables. When the CPU frequency is very low (about 100MHz), everything must be done in the fastest way. On the ARM platform, if you take other dependencies into account (limited memory, time for other codes and effiency of virtual machine), A-Star still seemed slow in game, even under optimization with binary heaps. The quickest way with an acceptable outcome which I found at last is similiar to the way of "go along the walls", however, key waypoints are integrated, and following optimization strategies are used:

1.Use memory pools to avoid too much malloc() and free(). Memory allocation needs a lot of time, especially on mobile devices. Programmers should be smart to use them in real time algorithms.

2.Limit path finding steps. For example, if the algorithm doesn't return any result in 32 rounds (that means the units cannot reach their destination in 32 steps), then just stop the present path-finding task to start the next one, and warn the player. This is to avoid those rare yet possible worst situations that may block the task queue.

3.Use a find-and-follow strategy. That means when player selects multiple units and orders them to move toward the same place, Only one unit's path finding will be done, and other units will follow his route.

That is REALLY AMAZING!!! I nearly cannot believe it when I heard the news. The game was developed by three people including me,  the other two are programmer Zhao and game artist Liu from Infiworks Inc. I must confess there are some games like this kind, but only ours have ever reached the 1st!!!

I had been working in Infiworks for part-time, and later we decided to made the "Dudu Rush". Mr.Zhao provided us with the game engine and I used Lua to adjust the game logic to make it enjoyable, while Mr.Liu did most of the game art. I thought it would be somehow successful because the idea is not too bad and Mr.Liu's drawings are REALLY perfect as well as the wonderful music, but I have never expected the game to be so popular. Anyway, this is the first iPhone app I designed. Much thanks to Mr.Zhao and Mr.Liu, Cheers!

Think of what I learned from Infiworks: Some advanced UI design skill, Some code optimization techniques for Cocoa platform, and the most important thing: I got familiar with Lua. The language is really cool and I will use it in my lab projects:)

Note: For Something Behind This Game Please Visit Here:)

Types of key can only be number or string, however values can be a table. Self reference (Loops) is supported.

function serialize(t)
    local parents={}
    local newbies={}
    local function genstring(tbl,parent)
        parents[tbl]=parent
        local t_tmp={}
        for e_key,e_value in pairs(tbl) do
            local key= type(e_key)=="number" and "["..e_key.."]" or e_key
            if type(e_value)=="table" then
                local cckey= parent..(type(e_key)=="number" and key or "."..key)
                if parents[e_value] then
                    table.insert(newbies,cckey.."="..parents[e_value])
                else
                    table.insert(t_tmp, key.."="..ser_table(e_value,cckey))
                end
            else
                table.insert(t_tmp, key.."="..e_value)
            end
        end
        return "{"..table.concat(t_tmp,",").."}"
    end
    return "do local ret="..genstring(t,"ret")..table.concat(newbies," ").." return ret end"
end

在新主楼呆了三年，最近才发现厕所的门居然是那个原理。强大。

其实我也不知道我这习惯是怎么养成的了，不过反正寝室晚上是回不去，真没法回去。且不说隔壁那几个到了晚上就鬼哭狼嚎的，屁g一回来怎么都觉得别扭。果然是有其父必有其子。

总之这寝室已不是我的寝室，北航也不是我的北航了。

最近居然发现屁g拿我的盆子泡他的臭袜子……做人怎么着也不能这样吧。联想其各方面行为，怪不得他暑假搞上的那个妞后来再也没见过了。会看上这种jp的女生，真是瞎了眼。

八点半了居然还是没人来。

写完这句话Z同学就来了。

突然想起来我有本书借了得有一个月没还了，还是新书……算下来也该有二十多块钱了吧。记得本科的时候H同学在图书馆欠过一次四十多块钱的书，然后向我哭诉。当时我感觉这就是天文数字么。现在怎么总也觉得这点钱好像不算啥。每天吃饭不小心就得吃个二十块钱呢。唉，变了变了……

又在校内发现一个八卦。某@尼哄的同学Z居然找了个@米国的高中学弟做bf。而且此学弟貌似是甩掉远在家乡的ex和这同学Z好上的。这这这，其中缘故谁能知晓啊……看看人家ex在校内上说自己被骗了，我一个旁观者都不忍心啊。虽说Z同学你也就我大两岁，找个学弟也不是不行，不过，何必要在这种异国+劈腿的狗血剧情里扮演个角色呢。我说这学弟你也是的，中国跟米国是异国，尼哄跟米国难道就不是？唉，记得当初刚知道的时候还以为又是一桩美事呢，现在看看，华袍下面果然总会有虱子的。

在校内上看了看这学弟的照片，颇猥琐。话说我在Z大这几个同学还真扯，谈的恋爱貌似到现在也没一个让人觉得有希望走到最后的。

算了，本来还想评论评论C同学跟S同学呢，突然发现自己连结婚年龄都不到，光顾着说人家干吗。

已经过去了的：小升初，中考，高半夜凉初透考，考研，每次都令人胆寒。抛弃所有其他的选择，最后总成为背水一战。我每次都有了不成功就再来一年的想法，却每次都侥幸过关。下一次即将到来，不管是为了什么原因，我只有奋力向前。

小升初：外语出成绩的前一天，把新乡那边拒掉了，唯一的选择，最后勉强过线。

中考：体育比别人低了十多分，最后勉强过线。

高半夜凉初透考：第一次高半夜凉初透考、保送节节失利，最后还考砸了的我，竟然由于爆冷这种N年不遇的事情而几乎逃脱了复读的命运。当然，勉强过线。

考研：保研没去，出国放弃，说真的，我的考研分数只不过排在中游，又不是本系的学生，如果不是面试，很可能会被刷掉的。最后能考上，也算幸运了。

在这一次的战斗前，我写下这样的文字，祝自己好运。