Insertion Bits Research Articles

Lock Isolation Security Architecture for Reconfigurable Scanning Networks

<p indent=0mm>To protect the reconfigurable scanning network from the influence of unauthorized access, tampering of transmitted data by malicious instruments and sniffing, a lock isolation security structure is proposed. Firstly, the presented structure divides the instruments without security threat to each other into one group, and the groups can be accessed one by one via the isolated signals, which can prevent malicious instruments tampering and sniffing transmitted data. Secondly, the key instruments are protected by the lock segment insertion bit. The lock segment insertion bit can only be opened when multiple key values at specific positions are set to specific values (0, 1 sequence), which can increase the difficulty of unauthorized access. Besides, to reduce the hardware overhead, and the difficulty of place and route caused by excessive instrument groups, instrument grouping algorithm is proposed. The proposed algorithm firstly constructs an undirected graph based on the security relationship among instruments. Then the maximal independent sets of the undirected are obtained. In this way, the number of instrument groups is reduced greatly. Compared to other similar methodologies, the experimental results conducted on ITC 02 benchmark circuits show that the time consumption for opening the locking segment insertion bit of the proposed security structure increased by 7 times, and the average percentage reduction of area, power consumption and wire length is 3.81%, 9.02% and 4.55%, respectively.

On-Chip Fault Monitoring Using Self-Reconfiguring IEEE 1687 Networks

Efficient handling of faults during operation is highly dependent on the interval (latency) from the time embedded monitoring instruments detect faults to the time when the fault manager localizes the faults. In this article, we propose a self-reconfiguring IEEE 1687 network in which all instruments that have detected faults are automatically included in the scan path, and a fault detection and localization module in hardware that detects the configuration of the network after self-reconfiguration and extracts the error codes reported by the fault monitoring instruments. To enable self-reconfiguration, we propose a modified segment insertion bit (SIB) compliant to IEEE 1687. We provide time analyses on fault detection and fault localization for single and multiple faults, and suggest how the self-reconfiguring IEEE 1687 network should be designed such that time for fault detection and fault localization is kept low and deterministic. We show that compared with previous schemes, our proposed network significantly reduces the fault localization time. For validation, we implemented a number of self-reconfiguring networks as well as their corresponding fault detection and localization modules in hardware, and performed post-layout simulations. We show that for large number of instruments, implementing the fault detection and localization module in hardware results in less area compared with the corresponding software-based implementation. Another benefit of the hardware implementation over its software counterpart is that to achieve the same fault detection and localization time, the hardware module can be clocked at a lower frequency than the core on which the corresponding software implementation would run.

A Secure Code Based Cryptosystem via Random Insertions, Deletions, and Errors

In this letter, a new code based cryptosystem with a public code is introduced. This cryptosystem is based on randomly flipping, deleting, and inserting bits into a codeword corresponding to a plaintext. The construction of a secure channel coding scheme using the proposed cryptosystem is presented. The key size and security of this scheme are analyzed. Not having the code as part of the key results in a key size comparable to many well-known symmetric key cryptosystems. It is shown that the best approach for an adversary to obtain the key has a very low success rate, which indicates that the cryptosystem provides excellent security.

Fine-Grained Access Management in Reconfigurable Scan Networks

Modern very large scale integration designs incorporate a high amount of instrumentation that supports post-silicon validation and debug, volume test and diagnosis, as well as in-field system monitoring and maintenance. Reconfigurable scan architectures, as allowed by the novel IEEE Std 1149.1-2013 (JTAG) and IEEE Std 1687-2014 [Internal JTAG (IJTAG)], emerge as a scalable mechanism for access to such on-chip instruments. While the on-chip instrumentation is crucial for meeting quality, dependability, and time-to-market goals, it is prone to abuse and threatens system safety and security. A secure access management method is mandatory to assure that critical instruments be accessible to authorized entities only. This paper presents a novel protection method for fine-grained access management in complex reconfigurable scan networks based on a challenge-response authentication protocol. The target scan network is extended with an authorization instrument and secure segment insertion bits that together control the accessibility of individual instruments. To the best of the authors’ knowledge, this is the first fine-grained access management scheme that scales well with the number of protected instruments and offers a high level of security. Compared with recent state-of-the-art techniques, this scheme is more favorable with respect to implementation cost, performance overhead, and provided security level.

Wavelength-Tunable Filters Utilizing Arrayed Waveguide Gratings for Colorless/Directionless/Contentionless Optical Signal Drop in ROADMs

The wavelength-tunable filter is a key device for creating colorless, directionless, and contentionless reconfigurable optical add-drop multiplexers. Although arrayed-waveguide gratings (AWGs) can realize compact and cost-effective tunable filters, crosstalk in wavelength-division-multiplexing systems increases as the frequency grid spacing decreases. To resolve this problem, we propose a tunable-filter architecture that can eliminate the crosstalk by utilizing two specific (commeasurable) cyclic AWGs in conjunction with multiple switches based on symmetric Mach-Zehnder interferometers and an asymmetric Mach-Zehnder interferometer (AMZI) filter. To verify the technical feasibility of the proposed architecture, we fabricate a monolithic prototype using planar-lightwave-circuit technology. We confirm, for the first time, its excellent performance by measuring insertion loss, polarization-dependent loss, and bit error ratios (BERs). Alternative tunable-filter configurations employing multiple AMZI-based filters are newly investigated for future applications.

Trellis-Based Detecting the Insertion and Deletion Bits for Bit-Patterned Media Recording

Bit-patterned media recording (BPMR) is one of the promising technologies for realizing an areal density up to 4 Tb/in2; however, it poses new challenges to read channel design, including the two-dimensional (2D) interference, media noise, and track mis-registration. Furthermore, the BPMR system encounters the insertion, deletion and substitution errors, which are primarily caused by mis-synchronization between the write clock and the island positions. In this paper, we propose a novel detection method that exploits the trellis structure to detect the occurrence of insertion/deletion bits. Specifically, the specific marker bits are inserted periodically inside an input data sequence before recording onto a magnetic medium. Hence, the branch metric calculation is monitored during the marker bits to determine if there is any insertion/deletion error in the system. Numerical results indicate that the proposed method can performs better than the conventional one in terms of the percentage of detection and the percentage of missed detection and false-alarm, especially at low signal-to-noise ratio scenario.

A New Approach to Data Encryption Based on the Synchronous Stream Cipher with Bit-level Diffusion

Most proposed stream ciphers are cracked through vulnerability of input and output. This paper is focused on the encryption function and the security tradeoff between pseudorandom number generators and the encryption function. Despite the focus on the security of the key generation, there is still considerable potential for attacks on the secret key as long as the encryption function leaks valuable information about the key to the attacker. Hence, it is important to study the possibility of constructing a new encryption model based on a stream cipher, while considering security and throughput tradeoffs. In this paper a new approach to data encryption based on its integration with a synchronous stream cipher is presented. This new approach is named the “Permuted Synchronous Stream Cipher” (PSSC). The sophisticated design of the PSSC for providing diffusion to stream ciphers allows it to be easily incorporated into most of the existing proposed stream ciphers to provide better security. The PSSC key stream is constructed from two parts, namely the key- bits and a corresponding diffusion maps. The method involves inserting random bits into the ciphertext followed by bit rotation and XORing bitwise. Therefore, any statistical pattern or information about the secret key that may be reflected in or leaked into the cipher’s output can be masked by performing simple bit diffusion on the ciphertext based on a pseudorandom sequence of diffusion maps. We believe that the proposed method can achieve a throughput rate that is fast enough for real-time data protection with better security.

Device Scaling Considerations for Nanophotonic CMOS Global Interconnects

We introduce an analytical framework to understand the path for scaling nanophotonic interconnects to meet the energy and footprint requirements of CMOS global interconnects. We derive the device requirements for sub 100 fJ/cm/bit interconnects including tuning power, serialization-deserialization energy, optical insertion losses, extinction ratio and bit error rates. Using CMOS with integrated nanophotonics as an example platform, we derive the energy/bit, linear and areal bandwidth density of optical interconnects. We also derive the targets for device performance which indicate the need for continued improvements in insertion losses (<8dB), laser efficiency, operational speeds (>40 Gb/s), tuning power (<100 {\mu}W/nm), serialization-deserialization (< 10 fJ/bit/Operation) and necessity for spectrally selective devices with wavelength multiplexing (> 6 channels).

Access Time Analysis for IEEE P1687

The IEEE P1687 (IJTAG) standard proposal aims at providing a standardized interface between the IEEE Standard 1149.1 test access port (TAP) and on-chip embedded test, debug and monitoring logic (instruments), such as scan chains and temperature sensors. A key feature in P1687 is to include Segment Insertion Bits (SIBs) in the scan path to allow flexibility both in designing the instrument access network and in scheduling the access to instruments. This paper presents algorithms to compute the overall access time (OAT) for a given P1687 network. The algorithms are based on analysis for flat and hierarchical network architectures, considering two access schedules, i.e., concurrent schedule and sequential schedule. In the analysis, two types of overhead are identified, i.e., network configuration data overhead and JTAG protocol overhead. The algorithms are implemented and employed in a parametric analysis and in experiments on realistic industrial designs.

A novel steganographic system with information integrity

We propose a novel steganographic system that is able to provide a high quality stego image in spite of the high capacity of the concealed information. The number of insertion bits in a pixel is different according to each pixel's characteristics. In addition to that, our system is able to verify whether if the secret information was sent from the sender correctly or if an attacker forged the secret message. We use two frequency coefficients in DCT domain to generate the symbol code to check the integrity of secret information.

Improved ROP in Ultrahard Rock

This article, written by Assistant Technology Editor Karen Bybee, contains highlights of paper SPE 99045, "ROP Enhancement in Ultrahard Rock," by M. Roehrlich and K.-U. Belohlavek, ExxonMobil Development Co., prepared for the 2006 IADC/SPE Drilling Conference, Miami, Florida, 21–23 February. Drilling the hard and very abrasive Bunter formation in northwest Germany has been a challenge for 40 years. Low rates of penetration (ROPs) and high tool wear are common. The full-length paper details the analysis of historical data and the combination of bits, motors, and other bottomhole-assembly (BHA) components to improve ROP. The combination of new impregnated bits, new downhole motors, and improved hydraulics was the basis for the improvement. Introduction The Bunter, a hard and very abrasive formation, typically at a depth of 8,000 to 12,500 ft, consists of layers of quartzitic sandstone and silificated claystone with a compressive strength of 30 to 50 ksi. In the past, typical ROPs in 12 1/4-in. sections were 3 to 6 ft/hr. In the 1970s and 1980s, 15 to 20 insert bits were required to drill the section and reaming was necessary as a result of undergauge bits. In the 1990s, a research project was initiated and funded by the German drilling industry to improve ROP in ultrahard and abrasive formations. In the past, the Bunter was characterized by the lowest ROP, shortest bit life, and highest cost per foot. Increasing the depth of cut (DOC) of impregnated bits in the Middle and Lower Bunter was identified as having potential for improvement. DOC means the length that is drilled with one revolution of the bit. An increase in DOC can be achieved by a decrease in overbalance or an increase in the amount of power available for drilling the rock. To analyze the key parameters, drilloff tests or drilling tests at fixed drilling parameters were conducted and plotted into Bingham diagrams. Within the German drilling industry, two approaches to increase ROP have been chosen—use of downhole turbines and use of high-speed downhole motors in combination with improved hydraulics made possible by larger-inside-diameter drillpipe. The full-length paper details results from downhole-motor runs with impregnated bits. All results are from 12 1/4-in. bits because this is the most common bit size used in Germany for the Bunter formation. Rotary Speed. Until 1997, the standard for high-speed downhole motors was 400 rev/min at 790 gal/min (360 hp). In 1997, a 9 1/2-in. downhole motor was tested in Germany at 780 rev/min at 849 gal/min (515 hp). In 2004, a new 9 1/2-in. downhole motor was developed that delivers 975 rev/min at 1,055 gal/min (1,025 hp). Weight on Bit (WOB). In 2004, the maximum WOB for high-speed downhole motors was approximately 48,100 lbm. With the 975-rev/min downhole motor, maximum WOB increased to 60,700 lbm because of improvements in bearings.

Slimhole Technology Maximizes Middle East Horizontal-Drilling Programs

This article, written by Technology Editor Dennis Denney, contains highlights of paper SPE 92376, “New Slimhole Technology Maximizes Productivity in Middle East Horizontal-Drilling Programs,” by Tariq Al-Wahedi, Mahmoud Abdel Hay, and Tamer Waheed, Abu Dhabi Co. for Onshore Oil Operations, and Bobby Grimes, SPE, and Sarvesh Tyagi, SPE, Hughes Christensen, prepared for the 2005 SPE/IADC Drilling Conference, Amsterdam, 23–25 February. Many operators use advanced slimhole drilling technologies throughout the Middle East. These programs involve new and re-entry wells with long horizontal sections, typically 6 or 6⅛ in. in diameter. A metal-sealed slimhole roller-cone bit was developed for use in these slim wellbores. The longevity of the new bearing has enabled operators to gain considerable confidence, which has translated into more on-bottom drilling time and longer drilled sections. Introduction Historically, tungsten carbide insert (TCI) bits with elastomer bearing seals were used to drill the slimhole sections, 6 in. in diameter in Abu Dhabi. In other Middle East countries, 6⅛ in. is the most common bit size. Typically in Abu Dhabi, the 6-in.-diameter hole section is drilled horizontally through the limestone reservoir (Shuaiba or Thammama group), sometimes crossing from zone to zone through a dense limestone. A tight tolerance requires geosteering to keep the well on target. The reservoir section is a porous and fractured limestone, with unconfined compressive strength (UCS) less than 5,000 psi. The UCS of the dense limestone caprock ranges between 12,000 and 15,000 psi. The section length typically varies from 3,000 to 4,000 ft, depending on the well, and sometimes extends to 6,000 ft. Two elastomer-sealed Intl. Assn. Drilling Contractors (IADC) 4-3-7-type bits were required to drill the 4,000-ft sections because of bit-use time limit. The instantaneous rate of penetration (ROP) is greater than 150 ft/hr, at times limited by data-capture speed of the measurement-while-drilling system. The additional trips for bit change-out cost rig time and increase the time that the reservoir is exposed to drilling fluid, which can result in greater formation damage. Horizontal sections through limestone reservoirs are drilled in several other countries in the Middle East (e.g., Saudi Arabia, Oman, and Kuwait). The section length varies depending on country, operator, and well type, but in general, the length of bit run is limited by the risk of lost cones after undetected seal failures, not by the cutting-structure wear. General Well Plan/Profile There are two general Abu Dhabi well plans and profiles. In Case 1, the 12¼-in. upper vertical section is drilled, and 9⅝-in. casing is set at the top of a massive shale formation. The 8½-in. section is drilled through the shale and limestone reservoir section while building inclination from vertical to horizontal. The massive shale formation is open in this type of well. In Case 2, the 12¼-in. upper vertical hole is drilled to the top of the reservoir section, where the 9⅝-in. casing is set in a limestone member or below to cover the shale formation.

Methods to Estimate the Rock Strength and Tooth Wear While Drilling With Roller-Bits—Part 2: Insert Bits

New methods to estimate both the rock strength and tooth wear while drilling with roller-bits were developed and proposed in Part 1. These methods were derived from the results of drilling tests using milled-tooth type three-cone bits with different amounts of tooth wear. In this report, these methods were extended and applied to insert type three-cone bits. The validity of the test and data analyses techniques of Part 1 were confirmed for insert bits. The methods to estimate the tooth wear proposed in Part 1 were based on the drillability strength of rock. A new approach to determine the tooth wear is presented. This new approach could be more readily applied to evaluating tooth wear when compared to the previous methods based on the drillability strength of rock.

坑底情報解析技術に関する研究（第３報） 岩石強度と刃先摩耗の推定方法のインサートビットへの適用性

The main objectives of this report are to confirm the applicability of the methods for the estimation of rock strength and tooth wear to insert bits. These methods were obtained from the test results of the milled tooth bits with different tooth wear as described in the 2nd report. Therefore, drilling tests were conducted using 101.6mm-dia insert bits with different tooth wear. The main results obtained from the tests are as follows: 1. The relation between the effective axial energy per revolution divided by bit diameter (Feu/Nd) and the effective rotary energy per revolution divided by cross-sectional area of bit squared ((8Te/d2)2), is the information which shows the rock strength independent of tooth wear. The drilling strength of rock (Ds) can be obtained from the relation between them.2. The relations between Ds and the penetration strength of rock (Is), Ds and the specific energy calculated from the effective rotary energy (Se), Ds and the threshold weight per unit length of bit diameter (Fc/d), are effective information to estimate the tooth wear quantitatively.From these results, it became clear that the methods for the estimation of rock strength and tooth wear obtained from the milled tooth bits are applicable to the insert bits.

Soft formation insert bits improve ROP and lower costs per foot : Grimes, B; Scott, D Oil Gas JV90, N33, 17 Aug 1992, P82–87

Soft formation insert bits improve ROP and lower costs per foot : Grimes, B; Scott, D Oil Gas JV90, N33, 17 Aug 1992, P82–87

Bits with diamond-coated inserts reduce gauge problems : Eckstrom, D Oil Gas JV89, N24, 17 June 1991, P41–43

In highly abrasive formations, failure of the gauge row cutters on tungsten carbide insert bits may occur rapidly, resulting in short bit runs, poor performance, and undergauge hole. In certain applications, polycrystalline diamond (PCD) enhanced insert bits have longer bit runs and maintain an in-gauge hole which reduces reaming time and wear on downhole equipment. These bits with PCD-coated inserts have reduced drilling costs in several areas of Canada. PCD has been applied to rock drilling tools for several years because of its high wear resistance. Polycrystalline diamond compact (PDC) bits use polycrystalline diamonds formed in flat wafers applied to the flat surfaces on carbide inserts. The flat PDC cutters drill by shearing the formation. Smith International Canada Ltd. developed a patented process to apply PCD to curved surfaces, which now allows PCD-enhanced inserts to be used for percussion and rotary cone applications. These diamond-enhanced inserts combine the wear resistance properties of diamond with the durability of tungsten carbide.

Performance Comparison of Rolling-Cutter Bits With Alternative Nozzle Designs

Summary Controversy exists regarding the optimum nozzle design for rolling-cutter bits. This paper describes the use of controlled laboratory conditions to isolate the true benefit of various hydraulic designs. Tests were conducted in a pressurized drilling environment with 9⅞-in. [251-mm] tooth and insert bits in Mancos shale. Hydraulic designs include combinations of standard- and directed-nozzle bits with center jets and long and short extended-nozzle bits. Results indicate that directed nozzles provide substantially better bit cleaning and rate of penetration (ROP) than the standard- and short extended-nozzle designs and a slightly faster ROP than long extended-nozzle designs.

Optimized Drilling Through Use Of Downnhole Motors

Abstract It has been established that rate of penetration (ROP) is directly related to rotational speed (RPM) of the drill bit in most formations. The Wembley area of northwest Alberta shows a proportionate increase in drilling rate with increases in rotary speed. Pan Canadian Petroleum Ltd. (PCP) optimized bit RPM by supplementing the rig's rotary capability with downhole motors. This paper will summarize the results of using downhole motors to Increase penetration rates in the Wembley field and will provide the drilling plan which PanCanadian uses to optimize vertical drilling with downhole motors. Introduction The relationship for soft and medium soft formations, between rate of penetration and rotational speed has been established as(1): (1) R = KWN a where: R = Rate of penetration K = Lithology factor N = Rotary speed W = Weight on bit a = exponent (equal to 1 for Wembley) For Wembley area this equation may be reduced to: (2) R = constant ( N ) Although the constant includes the bit weight, which is a variable, by drill off tests and manufacturer's recommendations bit weight has been optimized at a relatively constant value between 18 000 and 20 000 daN. Equation (2) suggests the rate of penetration can be enhanced through rotary speed increases. Factors which place an upper limit on rotary speed include:Drill string limitations.Drilling rig limitations on rotary speed.Drill bit limitations.Mechanical hole erosion.Casing wear. Drill string limitations include resonant vibration, joint strength, wear due to erosion and cyclic bending fatigue. Contractors limit rotary speed to 150 RPM or less and will not warrant the operational integrity of the string at higher rotary speeds. An excellent reference paper has been prepared by D. Dareing of Maurer Engineering Inc. (Ref. SPE 11228). Therefore most conventional drilling rigs are limited to rotary speeds of 150 RPM. Chain drive rotary tables are in common use and are usually coupled from the drawworks power take-off directly to the rotary drive pinion. Due to substructure space limitations it is not often possible to include a transmission on the rotary table. Chain sprockets also tend to be fixed by rotary torque requirements and chain speed limits. Torque tubes and electric drive rotaries have added flexibility to available RPM but these systems are not always available. Retrofit on existing rigs cannot be economically justified unless a long-term rig commitment is possible. Drill bit manufacturer's suggest RPM limits for their products but recent developments in premium sealed bearings have allowed greater flexibility. Also, insert bits have been improved in the bonding of carbide teeth to the cone matrix, allowing higher rotary speeds. Casing wear is a concern to all operators and, in some cases, optimum drilling performance has been sacrificed to limit wear. Non-rotating stabilizers have been used successfully but, again, stabilizer wear increases substantially when the drill string is rotated above 100 RPM.

Architecture of a nonnumerical accumulator

This paper presents the architecture of a nonnumerical accumulator which makes use of a specially organized associative memory. In contrast to a numerical accumulator, this nonnumerical accumulator is capable of matching, moving, inserting, deleting, altering, counting, and marking bits, characters, words, and sentences stored in the nonnumerical accumulator. In this paper, the configuration and instructions of the nonnumerical accumulator together with programming techniques for some applications are presented.

Rock Bit Technology - The Effect On Drilling Costs

Introduction The development of rock bits has been an evolutionary process. Modern-day rock bit technology had its beginning in 1909 with the introduction of the first rotary-cone rock bit. Since that time, rock bits have been continually improved. These improvements were highlighted by the introduction of the tricone bit in 1933, jet bits in 1948, tungsten carbide insert bits in 1951, sealed bearings in 1960, shaped and extended tooth-shape inserts in 1967, and journal bearings in 1970. The net effect of the rock bit evolution has been increased performance and reduced drilling costs. By ncorporating special lubricants in specially sealed cones, bearing life has been extended by maintaining a well-lubricated bearing and preventing the intrusion of mud and abrasives in the bearing. The development of tougher tungsten carbide materials has resulted in extended tooth-shape insert designs closely paralleling steel tooth bit configurations. This has permitted the use of longer-life insert bits in the faster drilling intervals. The long-life tungsten carbide cutting structure with sealed-lubricated bearing systems (roller and journal) has greatly extended bit life. Runs exceeding 100 hours and/or several thousand feet are not unusual. First Rotary Rock Bit On August 10, 1909, Howard R. Hughes patented the first rotary rock bit, which he called a "boring drill".(1) Prior to this time, the use of the rotary drilling process had been limited to soft formations because harder formations were difficult or impossible to drill using the scraping action of the drag bit. The initial rolling cutter bit resembled two pipe reamers set on journal bearings attached to a drill pipe sub (Fig. 1). This enabled the rotary drilling process to drill formations which were too hard to drill using the scraping action of the drag bit. The early designs utilized cones which did not mesh. Consequently, the bit "balled up" in soft shale rathereadily. This, along with the slower penetration rates, kept the bit from gaining wide acceptance during the early years and the drag bit remained as the more popular tool for drilling the soft formations encountered on the Texas Gulf Coast. Self-Cleaning Cones As the rotary process of drilling spread inland from Texas Gulf Coast, new formation combinations were encountered which created a serious problem. Inter-bedded layers of plastic shale and hard rock ledges often necessitated many round trips to alternate the drag bit with the rock bit. A bit was needed to drill both the hard and soft formations.(2) In 1925, this problem was solved with the introduction of a two-cone hit with intermeshing teeth (Fig. 2). As the teeth of one cone passed through the grooves on the opposite cone, accumulated formation was pushed from the grooves of the opposing cone – thus the name self-cleaning. The new cutting structure enabled the drilling industry, for the first time, to make hole through both soft and hard formations with a single bit, thus markedly reducing over-all time of each well. Anti-Friction (Roller) Bearings Until 1932, the basic bearing of rolling cutter hit remained the journal type.