Defense Articles

After years of modest growth, three-gun (rifle, shotgun, handgun) competition has become the hottest action shooting sport. When the International Practical Shooting Confederation (IPSC) was formed in 1976, its initial emphasis was on handgun competition. There was discussion about practical rifle and shotgun but not much progress. Committees were formed. the practical role of the rifle and shotgun debated. Actually there was a lot more talking than shooting.

There were a few major matches, notably the annual three-gun competition hosted by Soldier of Fortune magazine. Some clubs promoted three-gun enthusiastically, but with these few exceptions, three-gun took a while to catch on at the club level.
The first three-gun match I shot was in 1981. I used a Sako .222, a Mossberg 500 shotgun with a slug barrel, and a stock Colt Gold Cup .45 ACR The problems our club encountered were typical. Our facilities weren’t big enough for rifle competition. We had disputes about power floors for major and minor categories, debates about how to score buckshot of various sizes on paper targets.

The biggest obstacle to growth was cost. Through the ’80s and early ’90s it seemed you had to build a new handgun every year as compensators evolved, new cartridges caught on, high-cap frames and optical sights were introduced (back then there was no such thing as Limited or Production divisions). Maintaining a competitive handgun and keeping it fed was expensive enough without adding two more guns.
By the mid ’90s Open class handgun development stabilized, while Limited and Production divisions were introduced. Shooters had the novel experience of actually having money available in the gun budget. Cowboy action competitors were shooting three-gun matches and clearly having a good time.

Incidentally “three-gun” has come to mean matches where just one firearm type is used during a single stage. In “multi-gun” matches shooters may use two or three types in a single stage. The United States Practical Shooting Association (USPSA) which regulates IPSC competition in the U.S. promotes both types of matches.

Where 10 years ago you had to do some looking to find a three-gun match, today they are everywhere. An outstanding example is the annual DPMS Tri-Gun match, at St. Cloud, Minnesota near the manufacturing facility where DPMS makes high quality AR-type rifles.

The match is also sponsored by Brownells, distributors of gun parts and gunsmithing accessories. The match in August 2004 attracted more than 150 shooters including such superstars as Mike Voigt, Jerry Miculek, Matt Burkett, Jim Clark Jr., Tony Holmes, and Bruce Piatt.

The DPMS match recognizes four equipment divisions. In Open, pretty much anything goes–compensators, optical sights, bipods and shotgun speedloaders. Limited division is for iron sights only, no bipods or shotgun speedloaders. The DPMS match also recognizes a division called Tactical Limited, which permits optical sights on rifles only.

Finally, the “He-Man” (or “Heavy Metal”) division requires competitors to use .308-caliber rifles, manually operated 12-gauge shotguns, and .45 ACP handguns and no optical sights.

Handguns

Handgun action shooting has a long, well-established history. Briefly, you’ll need a safe, serviceable pistol or revolver, caliber 9mm Luger or larger, along with a secure holster, spare magazines or speedloaders. Eye and ear protection, of course, is mandatory in all shooting events.

Shotguns

Semiautomatic shotguns are universal in Open, Limited, and Tactical Limited divisions. A big advantage over slide actions is reduced recoil as gas-operated designs soak up a big chunk of recoil.

Remington 1100 and 11-87 shotguns are very popular; logically enough, as the 1100 has proven itself for more than 40 years, with parts and accessories such readily available.

Remington offers the 1100 Competition Master designed to be competition-ready out of the box. Its features include synthetic stock and forearm, extended eight-round magazine, oversized bolt handle, redesigned carrier and release for faster loading, and fiber-optic front sight.

I bought a CM over a year ago and like it very much. It has proven to be reliable, accurate, with amazingly soft recoil (partly due to the remarkable R3 recoil pad). Initially it shot nice groups with rifled slugs, but centered about a foot to the right. I had a Remington service center check it out. When it came back a few weeks later it was shooting right to point of aim.

Benelli shotguns with their extremely fast cycling time and high quality construction are likewise popular. Browning Gold shotguns have a clever speed-loading feature. If the gun is shot empty, with bolt locked back, there’s no need to drop a round in the chamber and release the bolt. Simply feed a round into the magazine and it is fed and locked into the chamber. Accessories for the Browning are a bit sparse at present, but a properly set up Gold would be highly competitive.

These networks would exploit the crossing of coplanar signal paths.

NASA’s jet Propulsion Laboratory, Pasadena, California

Architectures that would exploit the distinct characteristics of quantum-dot cellular automata (QCA) have been proposed for digital communication networks that connect advanced digital computing circuits. In comparison with networks of wires in conventional very-large-scale integrated (VLSI) circuitry, the networks according to the proposed architectures would be more compact. The proposed architectures would make it possible to implement complex interconnection schemes that are required for some advanced parallel– computing algorithms and that are difficult (and in many cases impractical) to implement in VLSI circuitry.

The difficulty of implementation in VLSI and the major potential advantage afforded by QCA were described previously in “Implementing Permutation Matrices by Use of Quantum Dots” (NPO-20801), NASA Tech Briefs, Vol. 25, No. 10 (October 2001), page 42. To recapitulate: Wherever two wires in a conventional VLSI circuit cross each other and are required not to be in electrical contact with each other, there must be a layer of electrical insulation between them. This, in turn, makes it necessary to resort to a noncoplanar and possibly a multilayer design, which can be complex, expensive, and even impractical. As a result, much of the cost of designing VLSI circuits is associated with minimization of data routing and assignment of layers to minimize crossing of wires. Heretofore, these considerations have impeded the development of VLSI circuitry to implement complex, advanced interconnection schemes.

On the other hand, with suitable design and under suitable operating conditions, QCA-based signal paths can be allowed to cross each other in the same plane without adverse effect. In principle, this characteristic could be exploited to design compact, coplanar, simple (relative to VLSI) QCA-based networks to implement complex, advanced interconnection schemes.

The proposed architectures require two advances in QCA-based circuitry beyond basic QCA-based binary-signal wires described in the cited prior article. One of these advances would be the development of QCA-based wires capable of bidirectional transmission of signals. The other advance would be the development of QCA circuits capable of highimpedance state outputs. The high-impedance states would be utilized along with the 0- and 1-state outputs of QCA.

A QCA-based wire for bidirectional communication (see Figure 1) would be terminated in two branches at each end - one branch for input, the other for output. To enable binary signals to propagate both from the left input to the right output terminal and from the right input to the left output terminal, it would be necessary to apply suitably phased clock signals (bias voltages) to QCA subarrays at various positions along the main wire and the end branches. (For complex reasons that must be omitted from this article for lack of space, such clocking is needed in any event to prevent spurious outputs. Here, the clocking would be exploited for the additional purpose of bidirectional communication.)

One especially useful interconnection network is an N x N crossbar network. A QCA circuit capable of a high-impedance output state would be needed to implement a crosspoint switch in a crossbar network. This is because while all N input lines cross a given output line, only one input line is allowed to put a signal on that output line; in other words, the connections between the other input lines and the given output line are required to be of high impedance in order to block signals.

Figure 2 depicts a proposed QCA– based crosspoint switch and a 3 x 3 crossbar network. The crosspoint switch would contain several branched QCA subarrays excited by suitably phased clock signals, and one of the quantum cellular automatons would serve as a control switch. The input signal I^sub i^ would propagate toward the output line along one branch and, by suitable clocking and coupling, would be converted to another signal, I^sub f^ propagating toward the output line along another branch. The application of a “0″ signal to the control switch would cause l^sub i^ and I^sub f^ to be of the same state (both 0 or both 1), thereby causing the signal Ii to be coupled onto the output line; in effect, the crosspoint switch would be in a low-impedance state. On the other hand, the application of a “1″ signal to the control switch would cause I^sub f^ to be the opposite of I^sub i^, thereby preventing coupling of either I^sub i^ or I^sub f^ onto the output line; in effect, the crosspoint switch would be in a high-impedance state.

This work was done by Amir Fijany, Nikzad Toomarian, Katayoon Modarress, and Matthew Spotnitz of Caltech for NASA’s Jet Propulsion Laboratory. For further information, access the Technical Support Package (TSP) free on-line at uwm corn/tsp under the Computers/Electronics category. NPO-20855

AUSTIN, Texas — Engineers now can use four new National Instruments (Nasdaq:NATI) 26.5 GHz PXI switch modules and the latest version of the company’s NI Switch Executive switch management software for PXI-based RF and microwave test applications. The switches, combined with the new per-path calibration capability of NI Switch Executive 2.1, offer modularity and programming flexibility for communication test systems.

The National Instruments PXI-2596, PXI-2597, PXI-2598 and PXI-2599 are multiplexers, SPDT relays and transfer switch modules designed for routing RF or microwave signals in automated test applications. The new modules offer 26.5 GHz switching in multiple PXI configurations for a complete switching solution on one platform. Using microwave relays from Radiall, each module is designed to operate with less than 1 dB insertion loss up to 26.5 GHz, minimizing impact on the test system and appearing almost invisible to signals at much lower frequencies. They are ideal for passing high-order harmonics from RF upconverters, such as the NI PXI-5671 2.7 GHz vector signal generator, or routing multiple sources to RF downconverters, such as the NI PXI-5660 2.7 GHz vector signal analyzer.

Engineers can use the NI PXI-2597 50-ohm terminated multiplexer to route signals while avoiding reflections in high-power applications. The PXI-2596 offers a higher-density, unterminated option with dual 6×1 multiplexer banks in the same module. The PXI-2598 and PXI-2599 operate as transfer switches or SPDT relays, respectively, for basic signal routing or inserting and removing components in a single path.

To configure and control these new RF/microwave switch modules, engineers can use NI Switch Executive 2.1, which introduces several new features for Excel integration, RF switching and switch system debugging. The updated software gives engineers programmatic access to settings on a per-switch route basis so they can store RF path calibration and parametric information, improving overall test system accuracy. With the new configuration programming interface, engineers can completely specify and configure their NI Switch Executive virtual device from any programming environment, including NI TestStand test management software, the NI LabVIEW graphical development environment, NI LabWindows/CVI ANSI C development software and Microsoft Excel. With this new functionality, engineers can import existing switch route documents created in Excel into the NI Switch Executive environment, making them easier to maintain and modify. The new release also features interactive switch control and debugging panels to further accelerate system development by visually specifying and viewing switch closures. NI Switch Executive delivers an intuitive programming interface, abstracting low-level switch programming and configuration from test applications greatly increasing test code reuse and switch system maintenance.

The PXI-2596, PXI-2597, PXI-2598 and PXI-2599 modules add to the more than 100 switch configurations available from National Instruments in the modular PXI and SCXI platforms. When combined with modular instruments and intuitive software such as NI Switch Executive, engineers can use these switches to form the building blocks of functional test systems, in-circuit testers or manufacturing defect analyzers in a variety of industries.

About NI Modular Instruments

NI offers essential technologies for test, which combine high-performance hardware, flexible software and innovative timing and synchronization technology for test and design applications. NI modular instruments offer accurate, high-throughput measurements from DC to 2.7 GHz. The product family includes:

–High-resolution digitizers (up to 24 bits, up to 250 MS/s)

–Signal generators (up to 16 bits, 200 MS/s)

–Digital waveform generator/analyzers (up to 400 Mb/s)

–Digital multimeters (up to 7 1/2 digits)

–RF vector signal generators and analyzers (up to 2.7 GHz)

–Dynamic signal analyzers (up to 24 bits, 500 kS/s)

–Switching (multiplexers, matrices and general purpose)

About PXI

PCI eXtensions for Instrumentation (PXI) is an open specification governed by the PXI Systems Alliance (www.pxisa.org) that defines a rugged, CompactPCI-based platform optimized for test, measurement and control. It is supported by more than 65 member companies and more than 1,150 products are available. PXI products are compatible with the CompactPCI industrial computer standard and offer additional features such as environmental specifications, standardized software and built-in timing and synchronization.

About National Instruments

National Instruments (www.ni.com) is a technology pioneer and leader in virtual instrumentation — a revolutionary concept that has changed the way engineers and scientists in industry, government and academia approach measurement and automation. Leveraging PCs and commercial technologies, virtual instrumentation increases productivity and lowers costs for test, control and design applications through easy-to-integrate software, such as NI LabVIEW, and modular measurement and control hardware for PXI, PCI, USB and Ethernet. Headquartered in Austin, Texas, NI has more than 3,600 employees and direct operations in nearly 40 countries. In 2004, the company sold products to more than 25,000 companies in 90 countries. For the past six years, FORTUNE magazine has named NI one of the 100 best companies to work for in America. Readers can obtain investment information from the company’s investor relations department by calling 512-683-5090, e-mailing nati@ni.com or visiting www.ni.com/nati.

San Jose, Calif.–Fujitsu Microelectronics Inc. (FMI) unveiled a second generation asynchronous transfer mode (ATM) backbone device–the first in a planned series of upgraded ATM products made using FMI’s 0.5-micron CMOS process technology. The MB86681 self-routing switch element (SRE-L), revealed last month in an exclusive preview (EN, March 4), is designed for 155-megabit-per-second ATM switching hubs, routers and network access controllers.

FMI’s announced ATM strategy remains focused on the 155M/ps standard for now, the company said. Reinforcing that goal, the company took its earlier 155M/ps SRE device, the MB86680 (EN, Aug. 30, 1993) and souped up the features, including increased output buffers, Early Packet Discard (EPD) capability and enhanced flow control.

Anticipating a June availability date, FMI last week debuted the MB86681 at the Networld +Interop trade exhibit in Las Vegas. The device will be packaged in a 208-pin LPFP, priced at $75 each in production volumes.

Designed for matrix interconnection, the MB86681 includes separate 8-bit z input and output ports operating at up to 25MHz. For larger capacity switches, the SRE-L matrices can be connected into Delta switch topologies.

Internal output buffers with a 146-cell capacity can be divided into a 121-cell low-priority queue and a 25-cell high-priority queue. A control bit in the routine tag determines cell priority and an enhanced flow control feature uses selective cell discard.

“With its large output buffers and sophisticated flow control capability, the SRE-L enables a significant improvement in high-end ATM systems by reducing queue delay and enhancing overall system efficiency,” said Barry Marsh, director of Enterprise Products for FMI.

FMI said it will continue to provide its first generation ATM products, even as the new devices are introduced. Other planned rollouts include a second generation SAR chip, a Synchronous Optical Network (SONET) framer, as well as a single-chip network interface card (NIC) combining the SAR and framer. Samples of the planned devices are expected within six months, the company said.

The arrival of Multi-Protocol Over ATM (MPOA) on the networking scene has been largely unheralded, considering its numerous benefits. In part, the problem rests with the name.

Mentioning it can prompt a response of, “Isn’t that what ATM’s supposed to do?” After all, most people expect ATM to be able to transport multiple protocols such as IP and IPX.

Also, many networks already transport a variety of protocols via another ATM technology called LAN emulation (LANE). So why is MPOA such a breakthrough?

Like any other technology, MPOA is designed to solve a problem. In this instance, it’s the problems created by today’s router-based networks, which are being swamped by the increasing wave of bandwidth-hungry applications demanded by users.
Related Results

Consider the evolution of a typical network, which began with a collection of users on a common, shared LAN — for example, an Ethernet segment. As the enterprise grew, additional segments were added and connected with bridges, then routers.

The number of and reliance on routers increased steadily over time as more and more users and applications were added to the network. As bandwidth demands outstripped the capabilities of Ethernet, a new backbone technology such as FDDI was implemented to solve the problem and maintain service guarantees.

Unfortunately, the reward for good network performance is demand for even greater performance — to support Web-browsing, whiteboarding, scheduling, multi-disciplinary teams, corporate intranets and, in the near future, multimedia that would amaze even the most jaded 13-year-old cybergame prodigy.

The-bottom line: raw bandwidth is no longer enough in a world where the network has evolved from useful business tool to strategic necessity. Today, network administrators must provide the bandwidth, along with several classes of traffic contracts with tight service guarantees.

The result is increasing pressure on the routers at the core of the typical network, accompanied by delays and painfully slow service that threaten the ability to meet those guarantees.

The immediate reaction is to add more routers — but it’s not necessarily the correct and certainly not the most cost-effective solution. Routers are expensive — a number of user studies peg the cost of router ports, in terms of price/performance, at five to 18 times the cost of ATM switch ports.

The price difference stems from the fact that routers rely on software and work in a connectionless paradigm. Most data passing through a router must be analyzed to determine where it will be directed and to check items such as filter lists — tasks typically performed by microprocessors running software. This analysis is neither cheap nor scalable, but it’s a necessity for every data packet transmitted.

Performance and cost are just two of the reasons why an increasing number of network architects are opting for ATM backbones. Since the early 1990s, ATM has demonstrated its value in thousands of mission-critical networks as an optimal solution in terms of price/performance, tighter quality of service (QoS), scalability, and inherent support for hybrid networks comprising data, voice, and video traffic.

Despite the advantages of ATM, two concerns continue to affect network architects’ decisions about adopting the technology: the need to provide ongoing support for non-ATM connected users, and the pressure to preserve existing network hardware and software investments.

Supporting non-ATM users is accomplished with the implementation of LAN emulation (LANE) over ATM, which allows an ATM network to emulate a physical LAN segment without the physical constraints, such as distance or maximum bandwidth, of a real LAN segment.

LANE is built entirely around Layer 2 of the protocol stack and deals in MAC addresses, making it completely transparent to Layer 3 protocols such as IP, just like the real LAN segments it emulates. In a typical LANE network, user devices are split across several of these emulated LANs (ELANs).

LANE enables network architects to build networks with an ATM backbone that supports Ethernet, token-ring, or FDDI clients connected via the legacy LAN to ATM switches, while servers and other high-bandwidth devices can be connected directly to the ATM backbone.

Traffic flows between users in an ATM virtual circuit, in hardware. The software-based problems of a router-based network disappear because 1) ATM using LANE adds a connection-oriented scheme that eliminates the need to analyze data packet-by-packet in every node, and 2) traffic forwarding is accomplished in hardware.

End of story? Not quite. Until recently, users in different ELANs still required a router that had been upgraded with an ATM interface to communicate, exposing the ATM network to the same old router problems.

Hence the need for MPOA. MPOA provides the AtM-based, connection-oriented path required for realizing the benefits of AtM — for example, QoS.

VIRTUAL ROUTERS

MPOA logically divides the operations of a traditional router in two and allows each function — route calculation and packet forwarding — to reside on different hardware platforms. With MPOA, these functions can be distributed throughout the network, forming virtual routers and providing important benefits:

It was only a few years ago that storage area networks (SANs) were exclusive to early-adopter technologists and those who could justify the return on investment (ROI) from what would be a large investment in hardware, software and expertise. Now that SAN ROI is considered proven and applicable to most enterprise data centers, SANs are one of the key information technology assets accelerating productivity and trimming the bottom line for today’s enterprise. Through this transition, SAN technology has evolved, with some of today’s most significant technology evolution occurring not in storage or application resources, but in the network that connects them.
Related Results

Historically, the network connectivity portion of the SAN has been purchased in conjunction with the storage array. Each time IT purchased new storage, it would be accompanied by network components (switches, cables, etc.) to allow connectivity to the application hosts. This incremental approach to storage networking was appropriate for the early stages of SAN deployment, as SANs were usually tactical rollouts associated with particular applications. However, project-oriented rollouts are giving way to a more strategic “backbone” architecture that is independent of particular storage and server resources and allows higher disk utilization through increased consolidation. As enterprise IT professionals begin to architect the storage network backbone, it is crucial to consider fundamentals that will serve through several data center lifecycles, including scalability, modularity, interoperability, visibility and control.

Scalability

To this day, many SAN deployments have consisted of tactical, project-oriented architectures. Built upon 8- and 16-port fabric switches, these “SAN islands” provide effective connectivity for a particular application or storage resource, but do not scale to meet enterprise-class, long-term requirements. To examine the scalability limitations of today’s fabric switches, it is important to understand the requirements for inter-switch links (ISLs) in typical core/edge fabric architectures.

IT professionals are now considering the opportunity to build a strategic, independent network infrastructure that will scale to meet the enterprise’s needs for the next several years–the storage network backbone. The storage network backbone provides connectivity for hundreds of storage and application resources without wasting costly ports to connect other switches.

The strategic independence of the storage network backbone has empowered enterprise IT professionals to build and manage a more universal, utility-based infrastructure that can scale beyond the limitations of traditional SAN fabrics. While there will always be tactical decisions based on individual SAN applications, and those applications may require specific network components for support, the most strategic network is one that can universally support a diverse set of requirements now and into the future.

Interoperability

A main focus of the storage network industry over the last few years has been to promote overall interoperability among SAN components. In order to break away from the exclusive “early-adopter” stigma, SAN deployments are expanding beyond unique and specific interoperability certifications, where connectivity purchases were an “accessory” to disk purchases. Traditionally, SAN configurations have been built using a series of “interoperability matrices” that include storage subsystems, host operating systems, HBAs and any other components in the data path. Referencing a matrix from one or a number of SAN vendors has traditionally been necessary for support agreements, but with the evolution of standards and the sheer volume of SAN components and versions, SAN interoperability and support has been elevated to a more mainstream implementation. It is no longer realistic to expect SAN architects to cross-reference interoperability matrices (some of which are nearly 1,000 pages), where vendors are adopting a more universal level of support.

Modularity

Network growth not only means being able to satisfy higher port count requirements, it also means being able to accommodate future rates, protocols and services. While the vast majority of today’s storage networks are being connected via 2GB Fibre Channel, enterprise IT organizations are anticipating the deployment of 4GB and 10GB Fibre Channel, iSCSI, Fibre Channel over IP and network-based storage services. However, building standalone networks for each new rate, protocol and service contradicts the strategic goal of building the storage network back-bones as an independent utility, and can significantly reduce the ROI associated with network infrastructure purchases.

The goal of the storage network backbone architecture is to be modular enough to accommodate future network directions in the least disruptive and most cost-efficient manner possible. In order to do so, the storage network must offer new levels of flexibility, fault tolerance and investment protection.

Abstract–A major cause of the steep declines of American oyster (Crassostrea virginica) fisheries is the loss of oyster habitat through the use of dredges that have mined the reef substrata during a century of intense harvest. Experiments comparing the efficiency and habitat impacts of three alternative gears for harvesting oysters revealed differences among gear types that might be used to help improve the sustainability of commercial oyster fisheries. Hand harvesting by divers produced 25-32% more oysters per unit of time of fishing than traditional dredging and tonging, although the dive operation required two fishermen, rather than one. Per capita returns for dive operations may nonetheless be competitive with returns for other gears even in the short term if one person culling on deck can serve two or three divers. Dredging reduced the height of reef habitat by 34%, significantly more than the 23% reduction caused by tonging, both of which were greater than the 6% reduction induced by diver hand-harvesting. Thus, conservation of the essential habitat and sustainability of the subtidal oyster fishery can be enhanced by switching to diver hand-harvesting. Management schemes must intervene to drive the change in harvest methods because fishermen will face relatively high costs in making the switch and will not necessarily realize the long-term ecological benefits.

Commercial fishing for demersal fishes and benthic invertebrates, such as mollusks and crabs, is commonly undertaken with bottom-disturbing gear that can inflict damage to seafloor habitats (Dayton et al., 1995; Engel and Kvitek, 1995; Jennings and Kaiser, 1998; Watling and Norse, 1998). Habitat damage from dredges and analogous gear, designed to excavate invertebrates that are partially or completely buried beneath the surface of the seafloor, is generally much more severe than the damage caused by bottom trawls (Collie et al., 2000). Furthermore, impacts on and recovery from bottom-disturbing fishing gear vary with habitat type; generally smaller effects and more rapid rates of recovery are found for infauna in sedimentary habitats and the most severe and long-lasting damage in biogenic habitats that emerge from the seafloor (Peterson et al., 1987; Collie et al., 2000). Such biogenic habitats include seagrass beds, fields of sponges and bryozoans, and invertebrate reefs. Biogenic reefs that provide important ecosystem services such as habitat for other organisms include not only tropical coral reefs but also temperate reefs constructed by oysters (Bahr and Lanier, 1981; Lenihan et al., 2001), polychaetes like Petaloproctus (Wilson, 1979; Reise, 1982), and vermetid gastropods (Safriel, 1975). The recovery of such emergent invertebrate reefs is a slow process because of the relative longevity of the organisms that provide structure for the reef after they die and because of the nature of reefs as accumulations of multiple generations of reef builders.

One widespread temperate reef builder, the American oyster (Crassostrea virginica, also known as the “eastern oyster,” Am. Fish. Soc.), has been especially affected by bottom-disturbing fishing gear as the target of fisheries. More than one hundred years of dredging and tonging oysters in the Chesapeake Bay and Pamlico Sound have caused severe degradation of the oyster reef matrix (deAlteris, 1988; Hargis and Haven, 1988), such that reef area and elevation have been dramatically reduced (Rothschild et al., 1994; Lenihan and Peterson, 1998). Reduction in reef height has a serious consequence for the oyster population because one function of naturally tall subtidal oyster reefs is to elevate the oysters up into the mixed surface layer of the estuary; this layer of mixed surface water allows them to avoid mass mortality from persistent exposure to seasonally anoxic and hypoxic bottom water (Lenihan and Peterson, 1998). Reef height and structure also control reef hydrodynamics (e.g., flow speed, turbulent mixing, and particle delivery and deposition), which influence oyster population dynamics and production (Lenihan, 1999). Consequently, harvest-related reef destruction and degradation are considered major factors that have led to declines of American oysters in many estuaries located along the coasts of the Atlantic Ocean and Gulf of Mexico (Lukenbach et al., 1999).

Loss of oysters and the biogenic habitat that they provide appears from archaeological and paleontological evidence to be a worldwide phenomenon in temperate estuaries (Jackson et al., 2001). Oyster loss hurts not only the oyster fishery but, more importantly, imperils the ecosystem services provided by the oysters. These include, especially, the provision of emergent habitat and reef-dependent prey resources for many fish and crustacean populations of commercial and recreational importance (Peterson et al., 2000; Lenihan et al., 2001; Peterson et al., 2003), the filtration of estuarine waters (Newell, 1988), and the promotion of estuarine biodiversity by provision of hard-bottom habitat in fields of mobile sediments (Wells, 1961).

DiCon Fiberoptics Inc., a manufacturer of fiber optic components, modules, and test instruments, announced commercial availability of a MEMS 1X8 Optical Switch, based on a micro-electro-mechanical system (MEMS) chip, as used in DiCon’s existing MEMS 1X4 Switch. The MEMS chip consists of a “3D” electrically movable mirror on a silicon support. Voltages applied to the MEMS chip cause the mirror to rotate on two axes, which changes the coupling of light between a common fiber and eight input/output fibers.

With only a single switching element in the optical path, the MEMS 1X8 Switch features low insertion loss, low power consumption, excellent repeatability, and C and L band operation. It is a non-latching device that acts as a shutter when the electrical power is removed. Samples are now available for customer evaluation. The MEMS 1X8 Switch is available in a laser-style 14-pin DIP package that incorporates a digital control interface, and integrated control electronics for calibration. Package dimensions are 20.8mm long (30.3mm including the ferrule) X 12.7mm wide X 7.5mm high.

The MEMS 1X8 Switch can be used to reduce the cost of channel or band monitoring within DWDM networks by connecting multiple fibers sequentially to shared test and monitoring equipment. The MEMS 1X8 Switch drastically reduces the size and cost of channel monitoring cards. Multiple MEMS 1X8 Switches can also be combined with DiCon’s existing 1X2, 1X4, On-Off, and 2X2 MEMS Switches, to implement larger fanin/fan-out 1XN switches, as well as MXN optical cross-connect switch matrices.

Rated 12 A, PXI-2585 and PXI-2586 are single-slot, 3U PXI modules with 10 channels each. Former is configured as 10×1 multiplexer, and latter has 10 independent SPST relays. Both products, rated for voltages up to 300 V ac/dc, can switch up to 3,000 VA in ac applications and feature power levels up to 300 W in dc applications. General-purpose PXI-2564 is single-slot, 5 A, 3U PXI module with 16 independent SPST relays and isolation voltage up to 150 V.

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New Modules Add to Growing Family of More Than 80 Switch Configurations

NEWS RELEASE - March 1, 2005 - National Instruments expanded its current offering of more than 80 switch configurations with the introduction of the NI PXI-258x series of 12 A switch modules and the NI PXI-2564 5 A switch modules. These modules are ideal for switching high-power signals in military, aerospace and automotive applications.

National Instruments PXI-2585 and PXI-2586 high-power switches are 12 A, single-slot, 3U PXI modules with 10 channels each. The NI PXI-2585 switch is configured as a 10×1 multiplexer and the NI PXI-2586 switch has 10 independent SPST (Form A) relays. Both switches have low-contact resistance and high-isolation voltage. The PXI-2585 and PXI-2586, rated for high currents (up to 12 A) and high voltages (up to 300 VDC/300 VAC), are ideal for switching power signals and loads in control applications and battery, power supply and automotive testing. In AC applications, the modules can switch up to 3,000 VA and in DC applications, the modules feature power levels up to 300 W. With the PXI-2585 and PXI-2586 modules, engineers can switch higher power signals in PXI than before with NI hardware.

The National Instruments PXI-2564 switch is a 5 A, general-purpose switch in a single-slot, 3U PXI module. It has 16 independent SPST (Form A) relays with low-contact resistance of less than 100 milliohms and high-isolation voltage up to 150 V. It includes over-temperature protection to ensure that the relays are never operational with power amounts in excess of their ratings. If they approach the rated value, the control circuitry opens the relay contacts. The PXI-2564 switch is ideal for switching medium-to-high-power signals and loads in military, automotive or automated test applications. Engineers can double the density of their systems at a similar power level and lower price per channel with this new module compared to previous offerings.

All of the new modules are rated at Measurement Category II (CAT II) for long lifetimes even in harsh electrical environments, delivering better protection and making the modules less susceptible to damage from voltage transients. The relay-count tracking on the modules reduces system downtime by signaling to the test engineer when it is time to replace the relay. With common signal connection options, multiple vendors can provide the type of connectivity the system requires at an affordable price for reduced setup time and cost.

These switches come with high-performance driver software that gives engineers the maximum flexibility for system programming with the new module. Engineers can manage and maintain the system with NI Switch Executive and NI TestStand from validation to manufacturing test. The new module works with the entire suite of NI modular instruments, and engineers can use NI LabVIEW, LabWindows/CVI and other common development environments to control the module for automated test applications.

About NI Modular Instruments

NI offers essential technologies for test, which combine high-performance hardware, flexible software and innovative timing and synchronization technology for test and design applications. NI modular instruments offer accurate, high-throughput measurements from DC to 2.7 GHz. The product family includes:

o High-resolution digitizers (up to 14 bits, up to 200 MS/s)

o Signal generators (up to 16 bits, 200 MS/s)

o Digital waveform generator/analyzers (up to 400 Mb/s)

o Digital multimeters (up to 71/2 digits)

o RF vector signal generators and analyzers (up to 2.7 GHz)

o Dynamic signal analyzers (up to 24 bits, 204.8 kS/s)

o Switching (multiplexers, matrices and general-purpose relays)

About PXI

PCI eXtensions for Instrumentation (PXI) is an open specification governed by the PXI Systems Alliance (www.pxisa.org) that defines a rugged, CompactPCI-based platform optimized for test, measurement and control. PXI products are compatible with the CompactPCI industrial computer standard that is supported by more than 60 member companies and more than 1,000 products. PXI offers additional features such as environmental specifications, standardized software and built-in timing and synchronization.

About National Instruments

National Instruments (www.ni.com) is a technology pioneer and leader in virtual instrumentation - a revolutionary concept that has changed the way engineers and scientists in industry, government and academia approach measurement and automation. Leveraging the PC and its related technologies, virtual instrumentation increases productivity and lowers costs through easy-to-integrate software, such as the NI LabVIEW graphical development environment, and modular hardware, such as PXI modules for data acquisition, instrument control and machine vision. Headquartered in Austin, Texas, NI has more than 3,400 employees and direct operations in approximately 40 countries. In 2004, the company sold products to more than 25,000 companies in 90 countries. For past six years, FORTUNE magazine named NI one of the 100 best companies to work for in America.

Along with NI USB-1359 communication adapter and NI-SWITCH Soft Front Panel software, NI USB mainframes deliver plug-and-play solutions for implementing high-channel-count switching systems. Products simplify troubleshooting and hardware setup and offer plug-and-play switch control for SCXI platform. They utilize PC USB port to control any SCXI switch and are offered in 4- and 12-slot models with NI SCXI-1000/1001 chassis, USB adapter, and high-voltage analog backplane.

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New Switching Hardware and Software Simplify Automated Test Setup and Troubleshooting

AUSTIN, Texas - May 10, 2005 - Automated test engineers now can significantly reduce switch system hardware setup time with the new National Instruments (Nasdaq: NATI) USB switch mainframes, which introduce plug-and-play switch control to the SCXI platform. With the release of the mainframes as well as the new NI USB-1359 communication adapter and NI-SWITCH Soft Front Panel software, National Instruments delivers a low-cost, plug-and-play solution for implementing high-channel-count switching systems.

Engineers can use the new NI USB mainframes to take advantage of the high-performance, industry-standard USB port found on most PCs to instantly control any SCXI switch. The four-slot USB switch mainframe includes an NI SCXI-1000 chassis, a USB adapter and a high-voltage analog backplane (HVAB). For higher-channel-count applications, automated test engineers can take advantage of the 12-slot USB switch mainframe, which includes an NI SCXI-1001 chassis, a USB adapter and a HVAB. With the HVAB, engineers can route signals between switch modules for matrix or multiplexer expansion, eliminating the need for external wiring between the modules.

The new NI USB-1359 communication adapter gives engineers the ability to quickly set up new switch systems or add USB functionality to their existing systems. With the easy-to-use, plug-and-play communication adapter, engineers can control an entire chassis of SCXI switch modules from any USB port, such as a laptop or desktop computer, an embedded controller or a USB hub. Using this functionality, engineers now can develop portable switching systems for applications such as remote data logging and man-portable field service systems.

The new NI-SWITCH Soft Front Panel software offers an interactive, graphical environment for troubleshooting, debugging or simplifying relay operations. With the new software, engineers can begin closing relays in their automated test applications in seconds. The software also provides an intuitive interface for easily viewing open and closed relays during application execution and clicking on specific relays for interactive troubleshooting and predictive maintenance.

National Instruments delivers a complete line of modular switch hardware based on PXI and SCXI with more than 100 configurations for automated test, data acquisition and control systems. Engineers can manage and maintain their switching systems with NI Switch Executive and NI TestStand from validation to manufacturing test. Each of these new products works with the entire suite of NI modular instruments, and engineers can use NI LabVIEW, LabWindows/CVI and other common development environments to control their automated test and switching applications.

About NI Modular Instruments

NI offers essential technologies for test, which combine high-performance hardware, flexible software and innovative timing and synchronization technology for test and design applications. NI modular instruments offer accurate, high-throughput measurements from DC to 2.7 GHz. The product family includes:

* High-resolution digitizers (up to 24 bits, up to 200 MS/s)

* Signal generators (up to 16 bits, 200 MS/s)

* Digital waveform generator/analyzers (up to 400 Mb/s)

* Digital multimeters (up to 71/2 digits)

* RF vector signal generators and analyzers (up to 2.7 GHz)

* Dynamic signal analyzers (up to 24 bits, 204.8 kS/s)

* Switching (multiplexers, matrices and general purpose)

About National Instruments

National Instruments (www.ni.com) is a technology pioneer and leader in virtual instrumentation - a revolutionary concept that has changed the way engineers and scientists in industry, government and academia approach measurement and automation. Leveraging PCs and commercial technologies, virtual instrumentation increases productivity and lowers costs for test, control and design applications through easy-to-integrate software, such as NI LabVIEW, and modular measurement and control hardware for PXI, PCI, USB and Ethernet. Headquartered in Austin, Texas, NI has more than 3,400 employees and direct operations in nearly 40 countries. In 2004, the company sold products to more than 25,000 companies in 90 countries. For the past six years, FORTUNE magazine has named NI one of the 100 best companies to work for in America. Readers can obtain investment information from the company’s investor relations department by calling (512) 683-5090, by sending an e-mail to nati@ni.com or by visiting www.ni.com/nati.