Grammar: The Past Simple Tense

Word List:

1. cryptography	криптография, шифрование
2. information age	век информации
3. cryptographic algorithm	алгоритм шифрования
4. cryptosystem	система шифрования
5. ad hoc	временный
6. Data Encryption Standard (DES)	стандарт шифрования данных, стандарт DES
7. national	гражданин
8. non-combatant	нестроевой, гражданский
9. work factor	показатель (фактор) трудозатрат, времени на расшифровку

The Advanced Encryption Standard

Cryptography was once the domain of generals and small children, but the advent of the Information Age changed that. In the early 1970s the National Security Agency (NSA) and the National Bureau of Standards (NBS) realized that noncombatant adults needed to protect their sensitive, but unclassified, information.

NBS issued a public solicitation for a cryptographic algorithm. IBM responded. The company submitted a cryptosystem with a 56-bit key. A conventional cryptosystem is considered secure when its work factor – the amount of time needed to decrypt – is about 2^{key length}. The new algorithm became the data Encryption Standard (DES). With narrow exceptions, products incorporating DES could not be exported.

A 1996 National Research Council report on cryptography policy recommended an immediate loosening of export controls. No changes occurred until 1998, when a $250,000 special-purpose machine built by the Electronic Frontier Foundation cracked a DES-encrypted message in 56 hours. At that point U.S. export controls were relaxed to permit DES in exported products. In recent months export controls have been lifted even further, with no limit on number of bits.

A DES replacement was overdue. In 1997 the National Institute of Standards and Technology (NIST, formerly the National Bureau of Standards) announced a competition for the algorithm’s replacement and held public meetings to discuss the criteria for a proposed Advanced Encryption Standard (AES). Key length was most important. A 1996 ad hoc committee argued 90 bits was currently the minimum key length needed to provide data security for twenty years. NIST sought that much security and more – encrypted files should remain confidential well after AES was retired. NIST settled on a minimum key length of 128 bits.

NIST allowed foreign submissions and foreign viewing of the candidates. A foreign national who wanted software implementations of the candidates could have them The person had to register with NIST and promise not to pass on the algorithms (even if obtained from another source). While within the U.S. export-control laws, in spirit, this system formed a contrast to the export rules so recently enforced regarding DES.

Focused Practice

I. Answer the following questions:

1. When did NBS realize that noncombatant adults needed
to protect their sensitive, but unclassified, information?

2. What did NBS issue a public solicitation for?

3. When is a conventional cryptosystem considered secure?

4. Could products incorporating DES be exported?

5. When did changes occur?

6. What did NIST announce in 1997?

7. Did NIST allow foreign submissions and foreign viewing
of the candidates?

II. Analyse the grammar structures underlined in the above text.

III. Speak on: DES replacement.

Unit 67

Grammar: Word Combination; that, this, the...the Construction

Word List:

1. photo-etching	фототравление
2. substrate	материал, подложка, нижний слой
3. hybrid microstrip	гибридная микрополосковая схема
4. stripline circuit	схема, выполненная на микрополосках (вместо проводов)
5. low loss tangent	низкое значение тангенса угла потерь
6. dielectric constant	диэлектрическая постоянная (параметр)
7. permittivity	диэлектрическая проницаемость (параметр)
8. z-cut	срез, перпендикулярный к оси Z
9. chip	многофункциональная микросхема
10. single crystal	монокристалл

Mm–Wave Hybrid Microstrip

This paper reviews the current hybrid microstrip integrated circuit technology applicable to receiver operating in the 30 to 110 GHz frequency range to meet the requirements of both the low and high volume categories.

The form of mm-wave integrated circuit (mm-wave IC) discussed is that based on hybrid thin-film stripline circuits, with chip devices mounted on a metalized quartz substrate.

An important aspect of mm-wave ICs, as for microwave integrated circuits (MICs), is the transmission line for connection between circuit elements. Open microstrip has found wide practical acceptance for MICs; this structure consists essentially of a strip conductor deposited onto a flat dielectric substrate.

As at lower frequencies, the microstrip transmission line circuit is normally realized by thin-film technology, with the conductor shape or circuit pattern determined by photo-etching.

The quality of the substrate also is important. Microstrip circuit applications require a well controlled dielectric constant, low loss tangent and good surface finish. Conventionally, high purity alumina is used up to about 20 GHz, but above this frequency there is an advantage in reducing the relative permittivity of the substrate material, together with reducing the substrate thickness. Also, the lower the permittivity, the larger the circuit; this is of benefit for circuit design realization and application of hybrid techniques.

Quartz meets all of these criteria. Single crystal Z-cut is preferred, however, as it provides the advantage of a higher expansion coefficient. Circuits may be arrayed during the thin-film fabrication process for production purposes.

The preferred microstrip structure dimensions for acceptable transmission propagation with Z-cut quartz are 500 μm wide lines on 250 μm thick substrate and 250 μm wide lines on 125 μm thick substrate at 26 to 40 GHz and 75 to 110 GHz, respectively, for 50 ohm characteristics. The measured line losses are negligible.

Focused Practice

I. Answer the following questions:

1. What technology does the above paper review?

2. Where are chip devices mounted?

3. What is an important aspect of mm-wave Ics?

4. Why is the quality of the substrate also important?

5. What are the preferred microstrip structure dimensions?

6. What are the measured line losses?

II. Analyse the grammar structures underlined in the above text.

III. Speak on: Mm-wave ICs.

CONTENTS

 

Предисловие.............................................................................	3
SECTION 1. PHYSICAL AND MATHEMATICAL SCIENCES....	4
Unit 1. “Guest-Host” Systems..................................................	4
Unit 2. Particle Simulations of the SPT...................................	6
Unit 3. Controlling Robots with the Mind...............................	8
Unit 4. Magnetron Sputtering...................................................	10
Unit 5. Particle-Induced Turbulence Attenuation....................	11
Unit 6. Tritium Pellet Injector Results.....................................	13
Unit 7. Fundamental Characteristics of a Fluid.......................	14
Unit 8. Enhancing Film Condensation Heat Transfer..............	15
Unit 9. Effects of Welding Parameters on Hard Zone Formation at Dissimilar Metal Welds..........................	17
Unit 10. Measurement and Analysis of Ultrasonic Beam Profiles in a Solid..........................................................	19
Unit 11. Review of Magnetic Methods for Nondestructive Evaluation (NDE)..........................................................	21
Unit 12. Impact of New Magnetoresistive Materials on Magnetic Recording Heads......................................	22
Unit 13. Progress in Membrane Science and Technology for Seawater Desalination.............................................	24
Unit 14. Asymptotic Methods in Turbulent Combustion..........	26
Unit 15. Membranes and Microorganisms.................................	27
Unit 16. What Materials Are Suitable as Polymer Electrolytes?..................................................................	29
SECTION II. ELECTRICAL ENGINEERING AND ELECTROMECHANICS........................................................	31
Unit 17. Fatigue Cracks in Turbine Discs..................................	31
Unit 18. The Split Shaft Design.................................................	33
Unit 19. Evaluating Individual Losses.......................................	35
Unit 20. Expert Systems for Fluid Power..................................	37
Unit 21. Expert System. Other Useful Features.........................	39
Unit 22. The Calculation of a Last Stage Low Pressure Steam Turbine and Exhaust Hood Flow..................................	41
Unit 23. Three-Stage Steam Turbine Flow Analysis.................	42
Unit 24. Thermal Computer Aided Design – Advancing the Revolution in Compact Motor................................	44

 

Unit 25. Demonstration of a Microfabricated High–Speed Turbine Supported on Gas Bearings.............................		46
Unit 26. Variable Speed Drives..................................................		48
Unit 27. Steam Chemistry and the Turbine................................		50
SECTION III. COMPUTER SCIENCE...........................................	53
Unit 28. Department of Defense Selects IBM Supercomputer for Navy to Triple Computing Power...........................	53
Unit 29. Mobility Management for VoIP Service: Mobile IP VS SIP...........................................................	54
Unit 30. Mobile Software Agents for Decentralised Network and Systems Management.............................................	56
Unit 31. “Grid”, the Technology of Distributed Calculation....	58
Unit 32. Wise Drivers................................................................	60
SECTION IV. ENERGETICS AND POWER ENGINEERING.......	62
Unit 33. Tools for Dynamic Analysis of the General Large Power System Using Time-Varying Phasers...............	62
Unit 34. Energy Problems and Nuclear Power Development in Japan.........................................................................	64
Unit 35. Large-Scale Economic Integration of Electricity from Short-Rotation Woody Crops..............................	65
Unit 36. Streamer Dynamics......................................................	67
Unit 37. High Temperature Superconducting Current Limiting Series Reactor...............................................................	68
Unit 38. Multi-Criteria Decision Analysis Techniques in Electric Power Systems Expansion Planning..........	70
Unit 39. Cogeneration and On-Site Production.........................	72
Unit 40. Petersburg Combined Cycle........................................	74
Unit 41. How Nuclear Power Works..........................................	76
Unit 42. Big Plans for Ocean Power Hinge on Funding and Additional R&D.....................................................	78
Unit 43. Analysis of Pressure Reducing Stations for Cogeneration.................................................................	80
SECTION V. MANAGEMENT, ECONOMICS AND LABOUR PROTECTION..................................................................................	82
Unit 44. Foreign Exchange.........................................................	82
Unit 45. Temperature Changes in Canada.................................	84
Unit 46. Environmental Tobacco Smoke...................................	85
Unit 47. Mathematical Challenges in Spatial Ecology.............	87
Unit 48. Energy Saving Technologies in Hospitals...................	89
Unit 49. Design of Containment for the Long-Term Isolation of Irradiated Fuel During Underground Disposal........	91
Unit 50. Energy Analysis on Power Plants Using Cold Energy of LNG..........................................................................	93
Unit 51. New Firing Technology...............................................	94
Unit 52. Mobile phones: a health risk?......................................	96
Unit 53. Mobile telephony biological impacts..........................	98
SECTION VI. MEASURING TECHNIQUES AND EQUIPMENT	103
Unit 54. Signal and Network Analyzers Span the Spectrum from Audio to Light......................................................	103
Unit 55. Confocal Microscopes.................................................	105
Unit 56. A Historical Review of Atomic Frequency Standards Used in Space Systems..................................................	106
Unit 57. A Display System for Phased Array Radars................	108
Unit 58. Special Issue on Wireless Communications................	110
Unit 59. Bluetooth in Wireless Communication.......................	111
Unit 60. Wrap-Speed Wireless..................................................	113
SECTION VII. SPECIAL TECHNICAL DECISIONS IN TV, TELEPHONY, ENCRYPTION, NANOTECHNOLOGY.................	116
Unit 61. Dynamics of an Adaptive Hybrid................................	116
Unit 62. Multilevel Converters as a Utility Interface for Renewable Energy Systems.....................................	117
Unit 63. Bandwidth Considerations for Multilevel Converters	119
Unit 64. A Model of Visual Adaptation for Realistic Image Synthesis........................................................................	121
Unit 65. A Better Way to Compress Images..............................	123
Unit 66. The Advanced Encryption Standard............................	125
Unit 67. Mm-Wave Hybrid Microstrip......................................	126