25,526 research outputs found
Improving the performance of outbreak detection algorithms by classifying the levels of disease incidence
No full textWe evaluated a novel strategy to improve the performance of outbreak detection algorithms, namely setting the alerting threshold separately in each region according to the disease incidence in that region. By using data on hand, foot and mouth disease in Shandong province, China, we evaluated the impact of disease incidence on the performance of outbreak detection algorithms (EARS-C1, C2 and C3). Compared to applying the same algorithm and threshold to the whole region, setting the optimal threshold in each region according to the level of disease incidence (i.e., high, middle, and low) enhanced sensitivity (C1: from 94.4% to 99.1%, C2: from 93.5% to 95.4%, C3: from 91.7% to 95.4%) and reduced the number of alert signals (the percentage of reduction is C1?4.3%, C2?11.9%, C3?10.3%). Our findings illustrate a general method for improving the accuracy of detection algorithms that is potentially applicable broadly to other diseases and regions
Wireless LAN
No full textHanya dalam beberapa tahun datangnya Wireless LAN sudah mampu menarik pasar jaringan lokal. Wireless LAN sangat dibutuhkan karena LAN tradisional tidak mampu menjawab kebutuhan masyarakat yang menginginkan jaringan yang bisa dipindah ke segala tempat (mobile system). Kesulitan awal Wireless LAN adalah kecepatan transmisi yang lambat, tetapi seiring dengan kemajuan teknologi membuat masalah ini dapat diatasi. Masalah lainnya adalah biaya yang diperlukan pada awalnya sangat mahal mengingat teknologi wireless saat itu tidak dapat menjawab secara cepat tetapi saat ini dengan kemajuan elektronika dan komunikasi yang begitu cepatnya membuat Wireless LAN menjadi pilihan yang tepat, di mana biaya dapat ditekan serendah mungkin dengan hasil yang optimal. Tulisan ini akan memperlihatkan teknologi wireless dipakai pada jaringan LAN, manfaat yang akan diambil, perkembangan yang ada dan konsep yang dapat dipakai
[[alternative]]The diversity and habitation of crabs in Lan-Yang River
No full text[[abstract]]ABSTRACT
The Lan-Yang River System occupies the whole Yi-Lan County, and the main river, Lan-Yang River, plays the significant role of the indicators of economy and environment in Lan-Yang plain. Yi-Lan River and Dong-Shan River join the River System by connecting with the mouth region of Lan-Yang River to develop an unique estuarine ecosystem.
In order to get more ecological information, the crab diversity survey was conducted from up-stream to down-stream of the Lan-Yang River; and the crab diversity and habitation in the tidal flat where the Dong-Shan River connected Lan-Yang River was set a site to study.
A total of seven families and twenty-eight species of crabs are found from the up-stream to down-stream of the Lan-Yang River; and four families and fourteen species in the tidal flat of the study site of the Dong-Shan River and Lan-Yang River connected area.
In the study of the habitation of crab community in the study site, data of three aspects has been collected during the high and low tide conditions and has been analyzed.
1. The material of substrate: samples analysis indicates that the substrate material is sand loam and doesn’t show much influence on seasonal changes and the tidal conditions.
2. Crabs sympatric relationship: the data confirms that five species: Uca arcuata, Uca borealis, Uca lactea, Tmethypocoelis ceratophora and Helice formosensis are dominant in daytime; two species: Chiromantes dehaani and Chiromantes haematocheir dominate in nighttime. In addition, it appears the different sympatric combinations in the high and low tide zones. And there is more diversity in the high tide zone.
3.The burrows：burrows in low tide zone are small, more in numbers and high density.
Overall, this study shows that the crab species distribution and the tidal conditions has close relationship, and this corresponds with hypothesis from predecessors.
The handedness of three dominant species of Fiddler Crabs: U. arcuata, U. borealis and U. lactea has been recorded. And the research shows that there is positive correlation of the side of major chela and burrow-emerging-entering.
Hope this study can provide a basis of ecological information of crabs for the further understanding about Lan-Yang River Ecology.
Design and Implementation of Multimode Carrier Recovery Circuit for Wireless LAN
No full text隨著科技的進步，數位無線區域網路通訊技術正在蓬勃地發展，為了因應系統單晶片時代的到來，近年來的設計傾向於把多個系統整合於單晶片的運用上，利用一些設計的技巧可以節省面積以及降低其操作所需的必v。
本論文主在描述一個可以整合IEEE 802.11b無線網路和Bluetooth短距離傳輸的多模組載波頻率回復電路。對二種規格中之數種調變，我們利用多模組的特殊設計及一些簡單的邏輯闡，使整塊迴路的操作頻率與輸入訊號的頻率相同，再利用輸入訊號形式的不同，選擇適當之相位偵測器來偵測出頻率的誤差。經迴路濾波器後，將訊號輸出到數值控制震盪器累加以查出所偏移的相位，最後由相位旋轉器調回原本所預期的載波頻率，達成回復的動作。本電路可用以抵抗數位無線通訊通道中的不理想因素，回復原本的頻率以便後端電路易於解調，同時能達到省電的效果。In this Thesis, we present a multimode carrier recovery circuit design with hardware implementation. We combine the two different Wireless LAN specifications: Bluetooth modulated in GFSK scheme and IEEE 802.11b modulated in several DPSK schemes. Using the input data mode to determine the suitable phase detector and loop filter bandwidth. We understand the bandwidth of loop filter plays an important role in this feedback loop. It dominates the loop stable time and helps the circuit to resist the channel noise. For low power consideration, gated clock is also used in this design, thus, the whole loop does not always operate on the highest frequency and the two-phase detector is not always on at the same time.
The whole loop spends about 10~35 μs to reach the stable state and meet the specification, that requires 128μs for a long preamble in IEEE 802.11b and 64μs for Bluetooth.. The power required is 2.38mW when operating in 8MHz for Bluetooth, and 11.71mW for IEEE 802.11b. The total chip has an area of 0.48*0.48mm2 and contains 14175 gates.LIST OF CONTENTS
ABSTRACT ……………………………………………………….……….....….. i
LIST OF CONTENTS ………………….………………………………………… iii
LIST OF FIGUIRES ………..…………………………………….……………. vi
LIST OF TABLES ……………..…………………………………………….……. ix
CHAPTER 1 INTRODUCTION ……………………………………….………. 1
1.1 Motivation ………………………………………………………………… 1
1.2 Thesis Organization ……………………………………………………..… 2
CHAPTER 2 WIRELESS LAN OVERVIEW ………………………………… 3
2.1 Introduction to Wireless Communication Systems ……………………… 3
2.2 The 802.11b WLAN ……………………………………………………… 7
2.2.1 Packet Format ……………………………………………………… 8
2.2.2 Direct Sequence Spread Spectrum Technology ……………………… 9
2.2.3 DPSK Modulation ……………………………………………….. 11
2.2.4 Backer Sequences ……………………………………………...... 15
2.2.5 CCK Modulation ……………………………………………….. 16
2.3 Bluetooth …………………………………………………………..…… 18
2.3.1 Packet Format …………………………………………………….. 18
2.3.2 Frequency Hopping Spread Spectrum Technology ……………….. 19
2.3.3 Gaussian Frequency Shift Keying Modulation ………………….…. 21
CHAPTER 3 CARRIER RECOVERY LOOP ……………………………….. 23
3.1 Channel Characteristics of WLAN ……………….……………………. 23
3.2 Carrier Recovery Loop …………………………………………………… 24
3.2.1 System Overview …………………………………………………… 25
3.2.2 System Analysis ……………………………………………………... 28
CHAPTER 4 MULTIMODE ARCHITECTURE …………………………..……. 33
4.1 Multimode Issue ………………………..…………….………………..…… 33
4.2 Multimode Carrier Recovery Structure ………………………………… 35
4.3 Gated Clock …………………………………………………………………. 36
4.4 De-Rotator ………………………………………………………………… 38
4.5 Phase Detector …………………………………………………………… 39
4.5.1 Modified Costas Detector …………………………………………… 40
4.5.2 Frequency Discriminator …………………………………………… 43
4.6 Loop Filter ………………………………………………………………… 45
4.7 NCO and Sine/Cosine Tables …………………………………………… 47
CHAPTER 5 HARDWARE IMPLEMENTATION …………………………… 51
5.1 Cell-Based Design Flow ………………………………………………… 51
5.2 Matlab Simulation Result ………………………………………………… 53
5.3 RTL Simulation Result ………………………………………………… 58
5.4 Physical Layout …………………………………………………………… 61
CHAPTER 6 CONCLUSION ………………………………………………… 63
REFERENCES ………………………………………………………………… 6
The diversity and habitation of crabs in Lan-Yang River
No full text[[abstract]]ABSTRACT
The Lan-Yang River System occupies the whole Yi-Lan County, and the main river, Lan-Yang River, plays the significant role of the indicators of economy and environment in Lan-Yang plain. Yi-Lan River and Dong-Shan River join the River System by connecting with the mouth region of Lan-Yang River to develop an unique estuarine ecosystem.
In order to get more ecological information, the crab diversity survey was conducted from up-stream to down-stream of the Lan-Yang River; and the crab diversity and habitation in the tidal flat where the Dong-Shan River connected Lan-Yang River was set a site to study.
A total of seven families and twenty-eight species of crabs are found from the up-stream to down-stream of the Lan-Yang River; and four families and fourteen species in the tidal flat of the study site of the Dong-Shan River and Lan-Yang River connected area.
In the study of the habitation of crab community in the study site, data of three aspects has been collected during the high and low tide conditions and has been analyzed.
1. The material of substrate: samples analysis indicates that the substrate material is sand loam and doesn’t show much influence on seasonal changes and the tidal conditions.
2. Crabs sympatric relationship: the data confirms that five species: Uca arcuata, Uca borealis, Uca lactea, Tmethypocoelis ceratophora and Helice formosensis are dominant in daytime; two species: Chiromantes dehaani and Chiromantes haematocheir dominate in nighttime. In addition, it appears the different sympatric combinations in the high and low tide zones. And there is more diversity in the high tide zone.
3.The burrows：burrows in low tide zone are small, more in numbers and high density.
Overall, this study shows that the crab species distribution and the tidal conditions has close relationship, and this corresponds with hypothesis from predecessors.
The handedness of three dominant species of Fiddler Crabs: U. arcuata, U. borealis and U. lactea has been recorded. And the research shows that there is positive correlation of the side of major chela and burrow-emerging-entering.
Hope this study can provide a basis of ecological information of crabs for the further understanding about Lan-Yang River Ecology.
PERANCANGAN APLIKASI PEMOGRAMAN TIK-TAK GAMES ON LINE PADA LAN
No full textalgoritma minimax diterapkan pada permainan TIK-TAK yang dimainkan oleh dua user yang berbeda dan terhubung dalam jaringan LAN serta pemain harus dalam posisi ON LINE. Permainan berbentuk papan dengan matrik berukuran 3x3, 4x4 , 5x5, 6x6, sampai 7x7. permainan yang dilakukan antara dua user maupun antara satu user dengna computer sehingga dapat membantu meningkatkan kecerdasan pada manusi
Using handheld pocket computers in a wireless telemedicine system
No full textObjectives: To see if senior emergency nurse practitioners can provide support to
inexperienced ones in a Minor Injuries Unit by using a wireless LAN system of
telemedicine transmitting images to a PDA when they were on duty. In addition,
whether such a system could be sufficiently accurate to make clinical diagnoses with
a high level of diagnostic confidence. This would permit an overall lower grade of
nurse to be employed to manage most of the cases as they arrive with a proportionate
lowering of costs.
Methods: The wireless LAN equipment could roam in the Minor Injuries Unit and
the experienced emergency Nurse practitioners could be at home, shopping or even
at a considerable distance from the centre.
Thirty pictorial images of patients who had been sent to the Review Clinic were
transmitted to a PDA various distances of one to sixteen miles from the centre. Two
senior emergency nurse practitioners viewed the images and opined on the diagnosis,
their degree of confidence in the diagnosis and their opinion of the quality of the
image.
Results: the images of patients were sharp, clear, and of diagnostic quality. The
image quality was only uncertain, as was the level of confidence of the diagnosis if
the patient was very dark skinned.
Conclusions: The wireless LAN system works with a remote PDA in this clinical
situation. However there are question marks over the availability of enough
experienced emergency nurse practitioners to staff a service that provides senior
cover for longer parts of the day and at weekends
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