scholarly journals Radio Astronomy and the CCIR

1991 ◽  
Vol 112 ◽  
pp. 288-295
Author(s):  
Vernon Pankonin
Keyword(s):  
Radio Astronomy ◽  
Study Groups ◽  
Space Research ◽  
Study Group ◽  
Consultative Committee ◽  
International Telecommunication Union ◽  
International Telecommunication ◽  
Special Event ◽  
Technical Advice ◽  
Group 2

ABSTRACTThe International Radio Consultative Committee (CCIR) is a permanent organization within the International Telecommunication Union (ITU). The purpose of the CCIR is to provide technical advice to the ITU and its various organs and members on the characteristics of the radio services which are governed by the International Radio Regulations, a product of the ITU. This is accomplished through reports and recommendations which may result from the regularly scheduled meetings of the CCIR or from meetings convened to prepare for a special event such as an upcoming World Administrative Radio Conference (WARC). The CCIR is divided into Study Groups. Study Group 2 covers Space Research and Radioastronomy. This paper describes the interactions of radio astronomers with Study Group 2. The radio astronomy related Study Questions currently before this Study Group are delineated, and the nature of the active reports and recommendations are discussed.

International Telecommunication Union

1957 ◽  
Vol 11 (3) ◽  
pp. 538-538
Keyword(s):  
Experimental Data ◽  
Technical Assistance ◽  
Study Groups ◽  
Great Difficulty ◽  
Consultative Committee ◽  
Sufficient Time ◽  
International Telecommunication Union ◽  
International Telecommunication ◽  
Definition Of ◽  
New System

The eighth plenary assembly of the International Radio Consultative Committee (CCIR) was held in Warsaw from August 9 to September 13, 1956, under the chairmanship of Professor Pawel Szulkin (Poland). The assembly elected with an absolute majority Dr. E. Metzler (Switzerland) as Director. The assembly considered a report which dealt with the activities of the fourteen established study groups as well as proposals to reorganize the study groups. The Warsaw decisions modifying procedures experimentally for the future were the outcome of proposals by the Organization and Finance Committees, the CCIR Secretariat and of discussions of the problem in the plenary assembly. The study groups were to remain the same in number and the allocation of work was in general the same, though it was felt desirable to give a more precise definition of their terms of reference. Among the resolutions adopted by the assembly, a number dealt with the length, content and quantity of documents submitted to the chairmen of the study groups, emphasizing that these should be as short as possible, as few as possible and that they should contain only the minimum indispensable mathematical formulae or numerical and experimental data. The new system was also expected to improve the position of distant countries which had so far experienced great difficulty in receiving preliminary documentation in sufficient time before plenary assemblies. The Technical Assistance Committee recommended the creation of a joint CCIR-International Telegraph and Telephone Consultative Committee (CCITT) committee to consider the ways and means whereby technical assistance was at present granted and to make suggestions for improvements, as far as telecommunication was concerned, to the ITU Administrative Council.

International Telecommunication Union

1954 ◽  
Vol 8 (2) ◽  
pp. 267-268
Keyword(s):  
Buenos Aires ◽  
Study Groups ◽  
Best Interests ◽  
Consultative Committee ◽  
International Telecommunication Union ◽  
Technical Aspects ◽  
International Service ◽  
International Telecommunication ◽  
Operational Methods

The seventh plenary assembly of the International Telegraph Consultative Committee (CCIT) of the International Telecommunication Union met in Arnhem, Netherlands, from June 5 through 13, 1953, under the chairmanship of Mr. van der Toorn (Netherlands). Most of the work of the session was carried on in study groups on the following subjects: 1) general telegraphy, 2) technical aspects of the establishment, operation and maintenance of telegraph channels, 3) technical aspects of telegraph apparatus, 4) vocabulary, symbols and classification, 5) phototelegraphy and facsimile, 6) technical aspects of switching in the service of start-stop apparatus, 7) European telegraph network operated by start-stop apparatus, 8) operational methods and quality of service, 9) services offered to users and rates other than telex rates, and 10) international service of telegraph subscribers and rates for such service. At the request of the Buenos Aires Plenipotentiary Conference of ITU, CCIT considered the possibility of amalgamating itself with the International Telephone Consultative Committee (CCIF) and concluded, by a vote of 16 to 11 with 1 abstention, that such a course would not serve the best interests of ITU. CCIT decided to hold its eighth plenary assembly in Geneva in the first half of 1956.

Comparison of anterior capsulotomy techniques: continuous curvilinear capsulorhexis, femtosecond laser-assisted capsulotomy and selective laser capsulotomy

2019 ◽  
Vol 104 (3) ◽  
pp. 437-442 ◽  
Author(s):  
Sheraz Daya ◽  
Soon-Phaik Chee ◽  
Seng-Ei Ti ◽  
Richard Packard ◽  
David H Mordaunt
Keyword(s):  
New York ◽  
Femtosecond Laser ◽  
Fracture Strength ◽  
Study Groups ◽  
Study Group ◽  
Linear Elastic ◽  
Group 2 ◽  
Human Eyes ◽  
Anterior Capsulotomy ◽  
Fellow Eyes

PurposeTo compare the anterior capsulotomy edge tear strength created by manual continuous curvilinear capsulorhexis (CCC), femtosecond laser-assisted capsulotomy (FLACS), and selective laser capsulotomy (SLC).SettingSingapore National Eye Centre, Singapore and Excel-Lens, Livermore, California, USA.DesignThree armed study in paired human eyes.MethodsCapsulotomies were performed in 60 cadaver eyes of 30 donors using CCC, Victus Femtosecond Laser, (Bausch & Lomb, Rochester, New York, USA) or CAPSULaser, (Excel-Lens, Los Gatos, California, USA). Three pairwise study groups each involved 10 pairs of eyes. Study group 1: SLC eyes compared with fellow eyes with CCC. Study group 2: CCC eyes compared with fellow eyes with FLACS. Study group 3: FLACS eyes compared with fellow eyes with SLC.A shoe-tree method was used to apply load to the capsulotomy edge, and Instron tensile stress instrument measured distension and threshold load applied to initiate capsule fracture. Relative fracture strengths and distension of CCC, FLACS and SLC were determined. Scanning electron microscopy (SEM) of capsule edges were reviewedResultsAnterior capsulotomies behave as non-linear elastic (elastomeric) systems when exposed to an external load. The pairwise study demonstrated that the SLC fracture strength was superior to that of CCC by a factor of 1.46-fold with SLC 277±38 mN versus CCC with 190±37 mN. Furthermore, CCC fracture strength was superior to that of FLACS by a factor of 1.28-fold with CCC 186 + 37 mN versus FLACS 145 ± 35 mN (p < 0.001). This was determined by statistical analysis utilising the Wilcoxon matched-pairs signed-ranks test and in accordance with the Consolidated Standards of Reporting Trials guidelines. The capsule edge of SLC on SEM demonstrated a rolled over edge anteriorly and an alteration of collagen.ConclusionsThe strength of the capsulotomy edge for SLC was significantly stronger than that of CCC which and both were significantly stronger than FLACS. The relative strengths can be explained by SEM of each type of capsulotomy.

scholarly journals Radio quiet, please! – protecting radio astronomy from interference

2009 ◽  
Vol 5 (S260) ◽  
pp. 457-464 ◽  
Author(s):  
W. van Driel
Keyword(s):  
Radio Astronomy ◽  
Radio Spectrum ◽  
Spectrum Management ◽  
International Telecommunication Union ◽  
Frequency Bands ◽  
International Telecommunication ◽  
Regulatory Limits ◽  
Regulatory Bodies ◽  
Precious Resource ◽  
Regulatory Measures

AbstractThe radio spectrum is a finite and increasingly precious resource for astronomical research, as well as for other spectrum users. Keeping the frequency bands used for radio astronomy as free as possible of unwanted Radio Frequency Interference (RFI) is crucial. The aim of spectrum management, one of the tools used towards achieving this goal, includes setting regulatory limits on RFI levels emitted by other spectrum users into the radio astronomy frequency bands. This involves discussions with regulatory bodies and other spectrum users at several levels – national, regional and worldwide. The global framework for spectrum management is set by the Radio Regulations of the International Telecommunication Union, which has defined that interference is detrimental to radio astronomy if it increases the uncertainty of a measurement by 10%. The Radio Regulations are revised every three to four years, a process in which four organisations representing the interests of the radio astronomical community in matters of spectrum management (IUCAF, CORF, CRAF and RAFCAP) participate actively. The current interests and activities of these four organisations range from preserving what has been achieved through regulatory measures, to looking far into the future of high frequency use and giant radio telescope use.

International Telecommunication Union

1955 ◽  
Vol 9 (4) ◽  
pp. 551-552
Keyword(s):  
Buenos Aires ◽  
Power Lines ◽  
Consultative Committee ◽  
Transmission Systems ◽  
International Telecommunication Union ◽  
International Operation ◽  
International Service ◽  
International Telecommunication ◽  
Considerable Debate ◽  
Carrier Systems

The seventeenth Plenary Assembly of the International Telephone Consultative Committee (CCIF) was held in Geneva from October 4 to 12, 1954, under the chairmanship of Mr. Wettstein (Switzerland). Delegates from 36 countries attended the Assembly, which in pursuance of a resolution of the Plenipotentiary Conference of the International Telecommunication Union (ITU) held at Buenos Aires in 1952, considered the possible amalgamation of the CCIF and the International Telegraph Consultative Committee (CCIT). After considerable debate, the Assembly by a vote of 21 to 13 with 1 abstention expressed the view that such an amalgamation would be in the interests of the ITU. Among the technical matters dealt with at the seventeenth Plenary Assembly were 1) the general switching program, 2) protection of telecommunication lines from danger and disturbances due to neighboring power lines, 3) protection of telecommunication cables from corrosion, 4) transmission, including telephone transmission in the international service, general characteristics of telephone circuits, the use of telephone circuits for telegraphy or phototelegraphy, broadcast and television relays over metallic lines, specification of carrier systems on metallic lines, radio relay links, links between mobile radiotelephone stations and international telephone lines, the maintenance and regulation of circuits and transmission systems, international operation and rates, and international signalling and switching; and 5) graphic and letter symbols, telephone vocabulary.

scholarly journals Changing trends and determinants of caesarean section using robson criteria in a government tertiary level hospital

2021 ◽  
Vol 10 (3) ◽  
pp. 1066
Author(s):  
Anjali Singh ◽  
Renuka Malik
Keyword(s):  
Caesarean Section ◽  
Caesarean Section Rate ◽  
Study Groups ◽  
World Health ◽  
Tertiary Level ◽  
Study Group ◽  
Group A ◽  
Group 2 ◽  
Group B ◽  
Level Hospital

Background: Robson Ten group classification system (TGCS) was proposed by World Health Organisation in 2014 for assessing, monitoring and comparing caesarean section rate between and within healthcare facilities. This tool was used in this study to analyse the determinants of caesarean section and compare with data of past.Methods: This observational comparative study was conducted at tertiary level hospital and included in study group A, 300 women delivered by caesarean section from November 2018 to November 2019 and in study group B, 300 women delivered by caesarean section from November 2015 to December 2016. The caesarean sections were classified as per TGCS to determine relative and absolute contribution made by each group to the overall caesarean section rate. The results were analysed to for determinants and change in trend.Results: In this study, the caesarean section rate in group A was 29.32% and group B was 28.03%. Group 2, 5, 1, 10 made the maximum contributions to overall caesarean section rate in both study groups. Group 2 was the largest contributor (25.00%) in study group A and 27.33% in study group B to overall caesarean sections.Conclusions: Implementing Robsons TGCS can help in comparing caesarean in an institution over a period of time and also among different institution at national and international level as a method of internal auditing, paving a way to rationalise and decrease Caesarean rate. 

scholarly journals International Telecommunication Union

1948 ◽  
Vol 2 (3) ◽  
pp. 536-537 ◽  
Keyword(s):  
The Netherlands ◽  
South African ◽  
Consultative Committee ◽  
International Telecommunication Union ◽  
Vice Chairman ◽  
International Telecommunication ◽  
Quality Of Transmission ◽  
Interim Period ◽  
Chairman Committee

The sixth meeting of the International Telegraph Consultative Committee was held in Brussels from May 10 to 27, 1948, the first meeting of the committee since 1936. C. Caenepenne, head of the Belgian delegation, was elected chairman of the conference, and E. C. Smith, head of the South African delegation, was elected vice-chairman. Committee reports presented to the conference included studies of the quality of transmission, standardization of telegraphic devices, relays, and general telegraphic and telephonic problems. Organizational matters for the interim period between meetings of the committee were discussed and a budget accepted. The seventh meeting of the Consultative Committee was scheduled for 1951 in the Netherlands.

International Telecommunication Union

1959 ◽  
Vol 13 (2) ◽  
pp. 321-321
Keyword(s):  
World Wide ◽  
Large Majority ◽  
Consultative Committee ◽  
International Telecommunication Union ◽  
International Telecommunication ◽  
European System

The Administrative Telegraph and Telephone Conference of the International Telecommunication Union (ITU) was held in Geneva, September 29–November 29, 1958, to revise the regulations in telephony and telegraphy adopted in Paris in 1949. By a large majority the Conference adopted the principle that the Telephone Regulations should be world-wide in scope. The Telegraph Regulations, however, were still to include provisions applicable only to Europe, with reference to rates in the European system, the phototelegraph service, and different rebates for press telegrams. The three resolutions concerning telegraphy which the Conference decided to include in the regulations which it adopted instructed the International Telegraph and Telephone Consultative Committee (CCITT) to study the possibility: 1) of making the provisions relative to the phototelegraph service world-wide in scope; 2) of modifying international alphabet No. 2 so that at least two additional signals from the figure case would be available to administrations or recognized private operating agencies for the needs of their internal services; and 3) of removing difficulties which still existed for the operational services and for the users in the counting of words. The Conference also made certain detailed changes in the Telegraph Regulations.

International Telecommunication Union

1950 ◽  
Vol 4 (1) ◽  
pp. 135-136 ◽  
Keyword(s):  
Civil Aviation ◽  
Consultative Committee ◽  
International Telecommunication Union ◽  
International Telecommunication ◽  
The World ◽  
European System

International Telegraph and Telephone Conference: The International Telegraph and Telephone Conference was held in Paris from May 23 to August 4, 1949 to amend the regulations drawn up at Cairo in 1938. In addition the conference considered questions referred to it by the International Telegraph Consultative Committee. Attention was concentrated on two items: unification of categories of telegrams; and tariff principles. The number of categories of telegrams was reduced from five to three, and all member countries were granted freedom to fix their own terminal and transit rates, as the conference abolished the Cairo regulation which had imposed restrictive rates for countries in the European system in their relations with countries in the extra-European system. The conference devised rules and a method of calculating rentals applicable to the joint use of circuits operated by start-stop apparatus in the European civil aviation system. The telephone regulations devised applied only to countries within the European system, whereas the telegraphy regulations were applicable throughout the world.

The International Telecommunication Union: Origin and Role

2021 ◽  
Author(s):  
Francis Lyall
Keyword(s):  
High Frequency ◽  
Study Groups ◽  
Radio Communication ◽  
Modern Life ◽  
International Telecommunication Union ◽  
Satellite Systems ◽  
International Telecommunication ◽  
International Body ◽  
Set Up ◽  
Modern Technologies

Integral to modern life, electrical telecommunications have to work within the constraints set by the unalterable laws of physics. Transborder systems require that technologies and protocols be harmonized if there is to be interconnectivity and interoperability. International agreements on wired services date back to the 1850s. Separate bodies set up to deal with international communications in east and west Europe, were brought together in 1865 in a single international body, the International Telegraph Union. Wireless communication—radio—presented the additional problem of broadcast signals interfering with each other. From 1906, it was regulated on the basis of principles that still undergird the modern arrangements, but no formal international body was established for the purpose. Instead, radio was dealt with by a sequence of plenipotentiary conferences. The separate regimes for wired and wireless services were united in 1932 when the International Telecommunication Union was established. The 193-member union is the UN specialized agency that deals with all forms of telecommunication. It underwent a major reconstruction in 1992–1994 in order to cope with modern technologies and now works within a four-year cycle. Its institutions are its plenipotentiary conference, a council, a secretariat, and three sectors responsible, respectively, for development, standardization, and radio communication. Each of these last three has a bureau and holds international world and regional conferences, and is aided by a large number of specialized study groups. In radiocommunication, that sector supervises the operation of the Radio Regulations, in which a Table of Allocations prescribes which radio frequencies are used for what purpose and maintains a Master International Frequency Register, which records the active frequency assignments made by states to transmitting stations under their control. Its work has increased markedly with development of high-frequency systems and the proliferation of satellite systems serving various purposes.

Sign in / Sign up

Export Citation Format

Share Document