The joy of mini-ITX

VIA EPIA 'Mini ITX' compact SBC (Single Board Computer)






Commell LV-675 -- [Dec. 14, 2005] -- Claimed to be the first mini-ITX board to support Pentium M and Celeron M processors with a 533 MHz front side bus (FSB), the LV-675 comes with drivers for embedded Linux.


Kontron 886LCD-M/mITX(BGA) -- [Nov. 2, 2005] -- A passively cooled, Linux-ready mini-ITX motherboard with a soldered-down BGA (ball-grid array) Intel processor and long-term availability, the 886LCD-M/mITX(BGA) has a 600MHz mobile Celeron processor, and targets cost-sensitive, low-power applications, such as POS (point-of-sales/service), gaming, banking, measurement, medical, and industrial computing.


Kontron 786LCD/mITX -- [Sep. 28, 2005] -- A mini-ITX board targeting cost-constrained, high-volume applications such as gaming, POS (point-of-sales/service), data communications, and medical equipment, the 786LCD/mITX is based on a mature Intel chipset yet supports USB 2.0, SATA, FireWire, and LVDS, Kontron says.


Arbor Technology ITX-i7435 -- [Sep. 27, 2005] -- A mini-ITX motherboard graced with a PCI Express x16 slot, and targeting multimedia, gaming, and other applications requiring high-quality graphics performance, the ITX-i7435 supports several Socket 478 Pentium M/Celeron M processors.


Kontron 886LCD/mITX -- [Aug. 28, 2005] -- A highly integrated mini-ITX motherboard with Pentium 4 and Celeron processor options up to 3 GHz, the 886LCD/mITX includes an AGP/DVO slot and targets CPU-intensive, cost-sensitive industrial applications.


Axiomtek SBC86800 board and EM603201 case -- [Jul. 7, 2005] -- A mini-ITX board supporting Intel Pentium-4 and Celeron processors, and available with a rolled steel micro-box with 180-Watt ATX power supply.


iBase MB720 -- [Apr. 29, 2005] -- A Via-based mini-ITX board that uses the same chipset used in newer Via mini-ITX boards, the MB720 is available with an LVDS module supporting 4:3 and 16:9 LCD displays. It targets industrial, gaming, medical, digital entertainment and other applications requiring stable and long lifecycle platforms.


Via ships dual-processor mini-ITX board -- [Mar. 11, 2005] -- Via is now sampling its first dual-processor mini-ITX board. The DP-310 features dual 1GHz Eden-N processors, along with gigabit Ethernet, SATA, a media-processing graphics system, and more. It targets high-density server systems, appliance servers, and compact embedded digital devices.

World's fastest Mini-ITX mobo? -- [Feb. 18, 2005] -- Powered by Pentium M processors at up to 2.3 GHz, the P620 Hawk is crammed with interfaces and expansion buses, and may also be the first Mini-ITX mobo to offer PMC expansion.


Coventive Uranus -- [Jan 4, 2005] -- A mini-ITX SBC (single-board computer) targeting Linux-based DVRs (digital video recorders), wireless TVs, network MPEG encoding boxes, and surveillance systems. The Uranus board is based on a MIP64 Toshiba SoC (system-on-chip), along with a Vweb MPEG coprocessor, and comes with a Linux SDK (software development kit).


Commell LV-667 -- [Dec. 17, 2004] -- Commell is shipping a mini-ITX board said to offer advanced graphics features, based on Via's latest northbridge. The LV-667 is available with a variety of video port options, and targets PVRs, set-top boxes, gaming machines, kiosks, POS (point-of-sales/service) devices, and more.


Toshiba mini-ITX-based PVR ref design -- [Oct. 18, 2004] -- Toshiba America Electronic Components (TAEC) has released a hardware/software reference design targeting digital multimedia appliances with sub-$100 BOMs (bills-of-material). The reference design, designated AVM49R, includes a mini-ITX board with a dedicated MPEG-1/2/4 codec chip alongside a 333MHz MIPS RISC-based SoC.


VIA dual-processor (DP) mini-ITX board -- Oct. 6, 2004 -- Via expects to ship its long-awaited "SP" mini-ITX board in November, followed in early 2005 by a "DP" model with dual nanoBGA embedded processors -- quite likely the world's first dual processor mini-ITX mobo. Both mini-ITX boards will feature a new northbridge supporting faster FSB (front-side bus), southbridge interconnect, and DDR memory speeds, and hardware MPEG-4 acceleration.


New VIA mini-ITX board targets vertically challenged apps -- June 24, 2004 -- VIA is shipping an ultra-low profile mini-ITX mainboard suitable for Linux-based flat TVs, LCD-panel computers, and other vertically challenged devices. The Epia MS uses a minimalistic I/O backplate and SODIMM memory for a slimmer form-factor, and is VIA's first mini-ITX board available with a fanless 1GHz Eden embedded processor.

Next-gen VIA mobo touts speed, security, MPEG-4 -- May 27, 2004 -- VIA will preview its next-generation mini-ITX board for the consumer electronics market at next week's Computex 2004 in Taipei. The EPIA SP features a new graphics and memory controller hub (GMCH) supporting faster front-side bus (FSB), memory, and southbridge interconnect speeds. It also features a C3 processor clocked at 1.3GHz, integrated PadLock Hardware Security Suite, and MPEG-4 acceleration.

Mini-ITX board boasts die-shrunk Pentium M -- May 25, 2004 -- Single-board computer vendor Lippert announced mini-ITX form-factor board support for Intel's new Dothan processor, a 90nm die-shrink of the Pentium M released today by Intel. The Dothan chip includes 170 million transistors, compared with 77 million on the previous Pentium M, making lots more room for on-chip memory caches, according to Lippert.

Centrino-like mini-ITX board available passively cooled -- Jan. 17, 2004 -- German single-board computer vendor Lippert is shipping a passively cooled version of its Centrino-like Thunderbird mini-ITX board based on an Intel Pentium M running at 1.3GHz. An actively cooled version running at 1.6GHz has been available since mid-December, 2003. Additionally, Lippert is readying a number of mini-PCI expansion devices and PCI riser cards for the boards.


Transmeta spins Crusoe-based mini-ITX mobo -- Jan. 07, 2004 -- Transmeta introduces two reference platforms to support device and system designs based on its Efficeon TM8600 and Crusoe TM5900 processors. Both platforms support Linux. Interestingly, the Crusoe TM5900 reference platform (pictured on the left) is implemented in the increasingly popular mini-ITX motherboard form-factor.


Mini-ITX P4M motherboard soars to 1700MHz and beyond -- Dec. 17, 2003 -- Taiwanese industrial computer board supplier Commell pushes the speed envelope for the compact mini-ITX mini motherboard form-factor, with the release of a mini-ITX board that supports Intel's mobile Pentium 4 processors at clock rates in excess of 1.7GHz.


Computing Client Development Center of Beijing launches low-end mini-ITX board for thin clients -- Dec. 11, 2003 -- The GSTB-3602 mini-ITX board and reference design kit is the very first product from Computing Client Development Center of Beijing, a joint venture between Advanced Micro Devices (AMD) and BLX IC Design Corp. Ltd.


First Pentium M based mini-ITX SBC runs Linux Sep. 03, 2003 -- Lippert GmbH introduces what is claimed to be the first mini-ITX form-factor motherboard to be based on an Intel Pentium M processor. The compact (6.7 x 6.7 in.) Thunderbird SBC features a Centrino-like architecture, with Intel northbridge and southbridge and a mini-PCI slot, and runs Linux, the company says.


2W ARM9-based mini-ITX board comes with Debian Linux -- Oct. 29, 2003 -- Simtec Electronics launches a mini-ITX based evaluation board that, in the highest specification of several available configurations, draws just 2 watts. The Simtec Samsung 2410 evaluation board is based on a Samsung S3C2410 ARM9 processor and is supplied with a Linux kernel, Debian cross-development environment, and several sample applications.


First mobile Pentium 4 mini-ITX SBC? -- Jun. 16, 2003 -- Commell announces what is claimed to be the first mini-ITX form-factor single-board computer (SBC) to be based on an Intel mobile Pentium 4 processor. Commell said its LV-670M SBC supports Linux and other embedded and desktop operating systems and targets VoD (video on demand), DVR (Digital Video Recorder), digital video broadcasting (DVB), streaming, surveillance, compression (MPEG), interactive servers, POS, Kiosk, ATM, Panel PC, transaction workstation, and terminal applications.


The joy of mini-ITX . . . -- Jun. 12, 2003 -- The Globe and Mail's "Chic Geek" Ian Johnson has discovered the mini-ITX motherboard form-factor, and he likes what he sees. In his article titled "Mini-ITX: Incredibly Tiny, eXceptionally cool," Johnson notes that "Mini-ITX motherboards are just starting to go mainstream, and they're real beauties if you want to save money and space. They're about the size of a CD jewel case and sell for between $75 and $200 (U.S.), depending on the speed of their built-in processor. All you have to do is add a case, memory and a hard disk, load an operating system and plug in a monitor, and you're off . . . "

MINI ITX

Mini-ITX is an ultra-compact (6.7 x 6.7 in.) mainboard form-factor developed by Via Technologies Inc. Mini-ITX targets a new generation of quiet, small footprint, connected, information and entertainment systems and enables the creation of an exciting new generation of small, ergonomic, innovative, and affordable embedded systems through its high level of integration and vastly reduced size of less than 33% that of the FlexATX mainboard form-factor.

The mini-ITX form-factor, as originally defined by VIA

VIA launched mini-ITX as a way to showcase its inexpensive chipsets for computer hobbyists, but the form factor has since gone into many other embedded markets. Its success has brought a vast proliferation of cases, power supplies, slim-line drives, Flash-to-IDE adapters, and other handy computing components that have helped drive the form factor into applications such as living room PCs and commodity hardware-based dense computing applications.

Additionally, the charms of mini-ITX have not been lost on industrial board vendors such as Kontron and others. Of course, it's important to note that mini-ITX motherboards from industrial single-board computer (SBC) vendors typically offer thicker PCBs, more rugged designs, and better build quality, compared with mini-ITX boards aimed at the consumer market. They also have correspondingly higher prices and minimum order volumes.

Single Board Computer EBX

The 5.75 x 8.0 in. Embedded Board eXpandable (EBX) specification, which was derived from Ampro's proprietary Little Board form-factor, resulted from a collaboration between Ampro and Motorola Computer Group.

As compared with PC/104 modules, these larger (but still reasonably embeddable) SBCs tend to have everything of a full PC on them, including application oriented interfaces like audio, analog, or digital I/O in many cases. Also it's much easier to fit Pentium CPUs -- whereas it's a tight squeeze (or expensive) to do so on a PC/104 SBC. Typically, EBX SBCs contain: the CPU; upgradeable RAM subassemblies (e.g. DIMM); Flash memory for solid state disk; multiple USB, serial, and parallel ports; onboard expansion via a PC/104 module stack; off-board expansion via ISA and/or PCI buses (from the PC/104 connectors); networking interface (typically Ethernet); and video (typically CRT, LCD, and TV).

Technical Seminar on Safety in Industrial Electrical Installation

THE IESL Sri Lanka

Electrical and Electronics Engineering Sectional Committee

Wednesday-May 30, 2007
Technical Seminar
on
Safety in Industrial Electrical Installation

by,
Eng Nuwan Kumarasinghe, Electronic Eng, Dept of Meteorology
(Earthing Techniques in Lightning Protection Systems)

Eng Chula De Silva ,Charted Electrical Engineer, & past president IESL, Consultant, Risk Manager Delmadge Insuarance Brokers Pvt. Ltd.
(Electrical Safety and Insurance concern)

Mr S Sivapaskeran, Former Deputy Commissioner of labour & factory inspecting Engineer
(Industrial accidents caused by improper use of electricity & case studies)

15.00-18.00 hrs

Wimalasurendra Auditorium
The Institution of Engineers Sri Lanka
120/15,Wijerama Mawata, Colombo 07

Refreshments and Course materials will be provided

World's First Quad Core Processor

Intel® Core™2 Quad processor

Intel’s most advanced processor just got an upgrade to the power of four—four processing cores for the ultimate in demanding entertainment

• Up to 54% better performance for intense multimedia applications, streaming movies, music, and more with powerful Intel quad-core technology¹
• Up to 53% better performance when enjoying immersive 3-D gaming²
• Up to 79% faster performance for highly-threaded applications when creating multimedia and 3-D content³
• Up to 8MB of L2 cache and 1066 MHz Front Side Bus for an unrivaled multitasking experience

Quad-Core Intel® Xeon® processor 5300 series

Breakthrough performance from the world's first quad-core processor for mainstream servers—faster, more powerful, and more efficient

• Great performance with energy efficiency
• Run applications with a smaller footprint
• Up to 50% better performance than Dual-Core Intel® Xeon® processor 5100 series within the same power envelope^
• Delivers the multitasking performance you need to maximize your virtualization efforts—enabling your enterprise applications to be responsive, even as you consolidate server resources

Intel® Core™2 Extreme quad-core processor

The world's best desktop processor for multimedia applications and the first to quad-core∇

• Up to 80% faster performance for highly-threaded appsΩ
• Four processing cores to handle massive throughput
• Based on leading Intel® Core™ microarchitecture, industry-first 8MB total cache

Extracted from www.intel.com

Supported Chipsets

These types will achive the best with latest intel processors (LGA775)

• Intel: 865PE/G/GV/G, 945P/PL/G/GZ/GC, P65P/G, 975X, P/G/Q965, Q963, 946GZ/PL; X/P/G/Q 3x
• NVIDIA: nForce4 Ultra/SLI X16 for Intel, nForce 570/590 SLI for Intel and nForce 650i Ultra/650i SLI/680i SLI.
• VIA: P4M800, P4M800PRO, P4M890, P4M900, PT880 Pro/Ultra, PT890.
• SiS: SiS662
• ATI: Radeon Xpress 200 and CrossFire Xpress 3200 for Intel

These mails are the updates of http://www.samitharansara.blogspot.com

Intel Rocks with Penryn

Penryn is the code name for Intel’s Next Generation Intel® Core™ 2 Family processor micro architecture. It is also the name of the industry’s first 45 nm microprocessor. It is an improvement on the Core Micro architecture introduced last year. It delivers more performance at the same clock speed compared to our Core 2 Duo processors.

It is a dual core product with a shared 6 MB L2 cache.

Intel’s 45 nm (65 nm-60 nm in Pentium IV Family) High-K Metal Gate Silicon Technology allows Penryn to run at higher clock frequency than its predecessor. It features 47 new Intel SSE instructions designed to enhance Media, Graphic and Gaming. We have measured >20% performance improvement on existing games compared to today’s fastest dual core processors, and more than 40 percent for gaming and video encoding with Intel SSE4 optimized video encoders. But of course, as with any performance claims “Your Mileage May Vary”.

Penryn-based processors provide faster divide performance with a Fast Radix-16 Divider, roughly doubling the divider speed over previous generations for applications such as scientific computation.

Up to 6MB of L2 cache per die (50% larger) enables greater performance across workloads; and increased associativity ( 16 way to 24 way) improves the utilization of the larger cache.

All of this fits in a compact 107 mm2 die featuring 410 million transistors!

The Penryn family enables optimized products for each of the target market segments from the high end Xeon all the way to mobile.

It will enable mobile optimized processors that provide greater performance within the existing mobile form factors and support lower processor idle power with Deep Power Down Technology. It also supports increased performance on single threaded apps with Enhanced Dynamic Acceleration Technology, which uses the power headroom of an idle core to boost performance of the non-idle core.

For the Desktop, there will be two versions that will ship at greater than 3GHz. A second generation Quad-core with up to 12 MB of L2 cache that will fit into existing QC power envelopes, and an energy efficient dual-core version with up to 6MB of L2 cache that will maintain the 65 W envelope.

For the Server and Workstation segment, the Penryn family will extend the leadership that the Xeon Processor family delivers today with dual and quad core products.This expect the combination of new 1600 MHz FSB for HPC segments, >3 GHz clock speed, microarchitecture enhancements and larger caches to deliver up to 45% improvement on bandwidth intensive floating point workloads compared to today’s fastest quad core processors. Some Java workloads exhibit up to 25 percent increase.

Source: Intel Tech Blog

Membership Functions

The membership function is a graphical representation of the magnitude of participation of each input. It associates a weighting with each of the inputs that are processed, define functional overlap between inputs, and ultimately determines an output response. The rules use the input membership values as weighting factors to determine their influence on the fuzzy output sets of the final output conclusion. Once the functions are inferred, scaled, and combined, they are defuzzified into a crisp output which drives the system. There are different membership functions associated with each input and output response. Some features to note are:

SHAPE - triangular is common, but bell, trapezoidal, haversine and, exponential have been used. More complex functions are possible but require greater computing overhead to implement.. HEIGHT or magnitude (usually normalized to 1) WIDTH (of the base of function), SHOULDERING (locks height at maximum if an outer function. Shouldered functions evaluate as 1.0 past their center) CENTER points (center of the member function shape) OVERLAP (N&Z, Z&P, typically about 50% of width but can be less).

Figure 5 - The features of a membership function

Figure 5 illustrates the features of the triangular membership function which is used in this example because of its mathematical simplicity. Other shapes can be used but the triangular shape lends itself to this illustration.

The degree of membership (DOM) is determined by plugging the selected input parameter (error or error-dot) into the horizontal axis and projecting vertically to the upper boundary of the membership function(s).

Figure 6 - A sample case

In Figure 6, consider an "error" of -1.0 and an "error-dot" of +2.5. These particular input conditions indicate that the feedback has exceeded the command and is still increasing.

ERROR & ERROR-DOT FUNCTION MEMBERSHIP

The degree of membership for an "error" of -1.0 projects up to the middle of the overlapping part of the "negative" and "zero" function so the result is "negative" membership = 0.5 and "zero" membership = 0.5. Only rules associated with "negative" & "zero" error will actually apply to the output response. This selects only the left and middle columns of the rule matrix.

For an "error-dot" of +2.5, a "zero" and "positive" membership of 0.5 is indicated. This selects the middle and bottom rows of the rule matrix. By overlaying the two regions of the rule matrix, it can be seen that only the rules in the 2-by-2 square in the lower left corner (rules 4,5,7,8) of the rules matrix will generate non-zero output conclusions. The others have a zero weighting due to the logical AND in the rules.

from
http://www.seattlerobotics.org

Why Use Fuzzy Logic ?

Why Use Fuzzy Logic?Here is a list of general observations about fuzzy logic:

• Fuzzy logic is conceptually easy to understand.
• The mathematical concepts behind fuzzy reasoning are very simple.
• What makes fuzzy nice is the "naturalness" of its approach and not its far-reaching complexity. Fuzzy logic is flexible.
• With any given system, it's easy to massage it or layer more functionality on top of it without starting again from scratch.
• Fuzzy logic is tolerant of imprecise data.
• Everything is imprecise if you look closely enough, but more than that, most things are imprecise even on careful inspection.
• Fuzzy reasoning builds this understanding into the process rather than tacking it onto the end. Fuzzy logic can model nonlinear functions of arbitrary complexity. You can create a fuzzy system to match any set of input-output data.
• This process is made particularly easy by adaptive techniques like ANFIS (Adaptive Neuro-Fuzzy Inference Systems). Fuzzy logic can be built on top of the experience of experts. In direct contrast to neural networks, which take training data and generate opaque, impenetrable models, fuzzy logic lets you rely on the experience of people who already understand your system. Fuzzy logic can be blended with conventional control techniques.
• Fuzzy systems don't necessarily replace conventional control methods. In many cases fuzzy systems augment them and simplify their implementation. Fuzzy logic is based on natural language.
• The basis for fuzzy logic is the basis for human communication. This observation underpins many of the other statements about fuzzy logic. The last statement is perhaps the most important one and deserves more discussion. Natural language, that which is used by ordinary people on a daily basis, has been shaped by thousands of years of human history to be convenient and efficient.
• Sentences written in ordinary language represent a triumph of efficient communication. We are generally unaware of this because ordinary language is, of course, something we use every day. Since fuzzy logic is built atop the structures of qualitative description used in everyday language, fuzzy logic is easy to use.

Extracted from a Mathworks Article.

Unmanned Surface vehicles

USVs will be equipped with:

• 
  

Sensor-based situation awareness

Dynamic route planning

Harbor and sea navigation, docking, evasive maneuvers

Dynamic reconfiguration and management of systems & resource

• 
  

Possible USV missions include:

• Persistent Intelligence Surveillance and Reconnaissance (using radar, EO/IR, SIGINT, CBN)
• Port & border security
• Special Ops support
• Autonomous search & rescue
• Communications relay (space, air, surface, special operations support; underwater)
• Maritime protection: anti-submarine, sea-skim missile, small boat Improvised Explosive Devices (IED)
• Track & trail
• Ice patrol
• Interdiction
• Force Protection
• Mine Detection and Neutralization
• Search and Recovery
• Forward Reconnaissance

Project to Refine a Prototype Unmanned, Tethered ADCP Platform for Measuring Streamflow

The Indiana District office developed a prototype tethered platform for making ADCP measurements from bridges and other structures.This prototype has been used successfully by a number of USGS district offices. The Kentucky District office also had developed a remote-controlled boat for conducting bridge-scour investigations. The Texas District office and the Corps of Engineers built remote-controlled boats based on the Kentucky design. Both of these platforms have invited much interest in the USGS because of the potential they offer in reducing exposure to hazards, particularly during streamgaging activities.

At the request of the USGS Chief Hydrologist, the Office of Surface Water Hydroacoustics Workgroup prepared a proposal for refining the design of the tethered and remote boats. This proposal was submitted to the USGS Instrumentation Committee (ICOM) and was funded.

The primary objective of the project is to develop and test designs for tethered and remote-controlled boats for increasing safety during streamgaging activities. The project included the following major tasks:

• develop specifications based on a survey of user needs;
• investigate various models of radio modems for wireless data telemetry;
• investigate commercial availability of boat hulls;
• test and evaluate prototype hulls;
• make designs available to USGS district offices.

Development of Specifications:

A written survey of user needs was sent to all USGS district offices and to other federal agencies known to use ADCP's. The survey asked users to specify desired features such as maximum boat length and weight.

Based on the 30 responses received, the following specifications were developed for a tethered platform:

• maximum weight with payload: 40 pounds;
• maximum length: 5 feet; maximum beam: 3 feet;
• maximum water velocity of rivers where the platform would be used: 12 feet per second;
• minimum acceptable time between battery replacement or recharge: 2 hours.

Investigation of various models of radio modems for wireless data telemetry:

To safely and efficiently acquire ADCP data from a tethered platform, data needed to be wirelessly transmitted from the ADCP to a laptop computer. It had previously been determined that a 900-MHz spread spectrum data modem could be used for this purpose. Approval from the USGS Water Resources Division radio liaison was obtained to use radios operating in the 900-MHz frequency range if the radios are license free under Part 15 of the FCC code. To use a licensed frequency in a government band will probably take 2 years (1 year for radio certification and 1 year for frequency assignment). However, the method used in initializing communication between the acquisition software and the ADCP caused limited compatibility with most wireless modems. After the problem was discussed with the manufacturer of the ADCP (RD Instruments), an alternate initialization method was implemented in the latest versions of Rio Grande firmware (10.07 and greater) and latest version of data-acquisition software (WinRiver 10.00).

A list of desired features then was developed for the radio modems. The desired features included

• reliably communicate with the ADCP, using the ADCP data-acquisition software provided by the manufacturer;
• have rugged, environmental housing;
• operate on 12-volt DC power; and,
• have 115,200-baud data-communication capability with the ADCP to maximize data throughput.

For a complete list of modems tested and for information on using radio modems with ADCP's, please see Use of Radio Modems with Acoustic Doppler Current Profilers.

Currently, the Freewave Model DGR-115 is the only modem tested that has met all of the desired specifications. More modems may be evaluated as they are made available for testing.

Investigation and testing of hull designs:

A review of possible off-the-shelf products that could easily be modified to meet the specifications was completed. Boat-builder literature, marine-supply catalogs, and the Internet were used in the literature search for off-the-shelf products. The research resulted in the purchase of a small, plastic catamaran designed to float a single person. The catamaran was modified for use with an ADCP and tested.

Hobie Floatcat modified for use with Rio Grande ADCP.

Discharge measurements in the field were completed to test this platform. The field tests revealed some major deficiencies: the platform exceeded the design-specification weight limit; the platform was difficult to control in the water; and the platform did not readily orient itself with the flow. These operational deficiencies were primarily a result of trying to apply a product designed for slow propulsion on a lake to use in faster river velocities. Recognizing these deficiencies led to having hulls built specifically for the tethered-platform application.

Private vendors were commissioned to construct prototype hulls specifically designed for making ADCP discharge measurements. The hulls acquired from the vendors for testing included two catamaran designs, two mono-hull designs, and three trimaran designs. The hull testing included tow-tank tests preformed at the USGS Hydraulics Laboratory at Stennis Space Center and field tests in which the platforms were used to make ADCP discharge measurements over varying flow conditions.

Field tests of the platforms included testing below a U.S. Army Corps of Engineers (USACE) Reservoir. The USACE increased the release of water from the reservoir during the testing to create higher flow conditions with velocities up to 7 ft/sec. During these tests, each platform was fitted with an RD Instruments Rio Grande ADCP and wireless 900-MHz spread spectrum modems. ADCP data were acquired using RD Instruments WinRiver software.

Field testing some platforms.

For the tow-tank tests, each platform tested was fitted with an RD Instruments Rio Grande ADCP and towed the length of the tank at varying speeds. Drag was measured for each platform with a strain-gage meter, which measured the force on the towrope. The drag each platform produced while being towed was recorded. The platforms were towed through the tank at speeds varying from 1 to 12 ft/sec to simulate the desired flow rates in which the platform might be used. During some of the tow-tank tests, wireless 900-MHz spread spectrum modems were used to acquire ADCP data that included the pitch and roll of the ADCP.

Platforms ready for testing at the USGS Hydraulics Lab.

Brief description of platforms tested:

Catamaran #1 is the original prototype catamaran platform as designed by the Indiana District office. This platform is constructed of polystyrene-foam floats built from a composite of several layers of 2-inch-thick standard insulation cut into a semi-vee shape.

Catamaran #2 is a catamaran platform built by Wanamaker Pontoon and Paddle Company. This platform is constructed of molded ABS plastic and is close in size and hull shape to the original prototype platform (Catamaran #1).

Catamaran #3 is a catamaran platform built by The OceanScience Group. This platform is constructed of shaped foam covered in a thin layer of fiberglass.

The OceanScience Group built all three trimaran platforms. All of the trimarans had large center hulls with small outriggers. The same outriggers were used on all three platforms. The outriggers were constructed of molded fiberglass. The center hull for Trimaran #1 was constructed of shaped foam covered in a thin layer of fiberglass. The fore and aft of this hull were symmetrical, coming to a thin edge at the ends of the hull. The center hull for Trimaran #2 was constructed of molded fiberglass and had more of a wedge or triangle shape. Trimaran #3's center hull was constructed of molded fiberglass and was longer than the center hull of Trimaran #2.

Mono-hull #1 was a single-hull platform built by Kann Marine. The platform was constructed of aluminum and had a flat-bottom-hull design with three fins on the bottom of the hull for added directional stability.

Mono-hull #2 was a single-hull platform built by The OceanScience Group. This platform was constructed of fiberglass with a vee-shaped-hull design and two fins on the bottom of the hull for added directional stability.

Summary of test results:

The results of the testing indicate that while any of the designs could be used under certain conditions, the best all-around performance under a range of conditions resulted from the trimaran designs.

The ADCP was mounted in the hull of the mono-hull platforms. The vee-shaped mono-hull platform (Mono-hull #2) performed well in the drag test (Table 1) but stability results were less than optimal. Both mono-hull platforms had more erratic motion and were more sensitive to flow disturbances or turbulence in the water than the other platform designs.

The ADCP was mounted between the two hulls of the catamaran platforms. A higher drag resulted at higher velocities when compared to the mono-hull designs (Table 1) because of the shape of the ADCP. The catamaran platforms were more stable than the mono-hull platforms.

The ADCP was mounted in the center hull of the trimaran platforms. The trimaran platforms had lower drag while still retaining the stability of the catamaran designs (Table 1). The trimaran's advantage is realized by combining the drag efficiency gained by placing the ADCP in a hull with two outer hulls that give added stability. Placing the ADCP in a hull also has the observed advantage of lowering the flow disturbance around the head of the ADCP.

Current testing and evaluation has focused on platforms with an RD Instruments profiler because 95 percent of the profilers in use by USGS for streamgaging are RD Instruments units. Sontek also manufactures an acoustic Doppler profiler (ADP) designed to make moving-boat discharge measurements. Similar results are expected with the Sontek units when used with the tested platforms, except that the overall drag may be less for the smaller size ADP's. If funding is available, additional testing of such units may be done.

Also, it is recognized that other brands or models of river-discharge-measurement devices that can use a tethered platform may become available. Current tethered-platform designs may need slight modifications in order to be used with new devices, or new tethered-platform designs may be more desirable.

Platforms available for purchasing:

The OceanScience Group, the manufacturer of the three trimaran platforms tested, has indicated that they will begin production of a fiberglass trimaran platform by the first quarter of 2001. This platform will be based upon the trimaran prototypes tested and specifically will be designed for use as a tethered platform for use with a Rio Grande ADCP. The center hull of the trimaran will have access ports where a wireless modem and a 12-volt battery used for powering the ADCP and the modem will be housed. OceanScience Tethered Boat Pictures.

Wanamaker Pontoon and Paddle Company, the manufacturer of Catamaran #2, has indicated that they are beginning production of a molded ABS plastic catamaran platform. This platform will be based upon the design tested and specifically will be designed for use with a Rio Grande ADCP. The two hulls will have access ports where a wireless modem and a 12-volt battery used for powering the ADCP and modem will be housed. While the catamaran design has higher drag, it should prove to be a good low-cost alternative for use in conditions with velocities below 6 ft/sec.

Sontek offers a catamaran system designed for use with their Mini-ADP. This package includes an aluminum catamaran-type platform and wireless modems. The Sontek platform has not yet been tested as part of this project.

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