Search

SELECT is an experimental system for assisting in the formal systematic debugging of programs. It is intended to be a compromise between an automated program proving system and the current ad hoc debugging practice, and is similar to a system being developed by King et al. of IBM. SELECT systematically handles the paths of programs written in a LISP subset that includes arrays. For each execution path SELECT returns simplified conditions on input variables that cause the path to be executed, and simplified symbolic values for program variables at the path output. For conditions which form a system of linear equalities and inequalities SELECT will return input variable values that can serve as sample test data. The user can insert constraint conditions, at any point in the program including the output, in the form of symbolically executable assertions. These conditions can induce the system to select test data in user-specified regions. SELECT can also determine if the path is correct with respect to an output assertion. We present four examples demonstrating the various modes of system operation and their effectiveness in finding bugs. In some examples, SELECT was successful in automatically finding useful test data. In others, user interaction was required in the form of output assertions. SELECT appears to be a useful tool for rapidly revealing program errors, but for the future there is a need to expand its expressive and deductive power.

Raster scan computer graphics with “real time” character generators have previously been limited to alphanumeric characters. A display has been described which extends the capabilities of this organization to include general graphics. Two fundamentally different scan conversion algorithms which have been developed to support this display are presented. One is most suitable to noninteractive applications and the other to interactive applications. The algorithms were implemented in Fortran on the CDC6400 computer. Results obtained from the implementations show that the noninteractive algorithms can significantly reduce display file storage requirements at little cost in execution time over that of a conventional raster display. The interactive algorithm can improve response time and reduce storage requirements.

The relative peakedness of diotic ABX discrimination functions for certain speech stimuli and the relative magnitude of the right ear advantage that they yield in dichotic listening tasks have been thought to be functionally parallel measures of speech processing. The results of the present study suggest that this is not always the case.

The years preceding World War Two witnessed significant changes in British policy in Palestine. These changes were at one and the same time the cause and effect of a radical re-adjustment of the British policymaking machine (for want of a better name) responsible for Palestine. Until 1936, Britain had administered the Palestine Mandate in the light of a reasonably objective judgement of the respective rights of Zionists and Arabs. To a considerable degree, policy-making had been delegated by Cabinet and Colonial Secretary to the permanent officials in London and to the men on the spot in Palestine. But the Arab Rebellion which began in April, 1936 and continued intermittently until the eve of war, involved the moral sympathy, political support and even the physical intervention of certain of the Arab States. The increasing involvement of the Arab world in Palestinian affairs of necessity led to an increasing and ultimately dominating interest on the part of the Foreign Office. With the security of the whole Eastern Mediterranean at stake policy in Palestine could no longer be left in the hands of officials, whether in London or Jerusalem. London could no longer afford the luxury of considering the problems of Palestine in isolation from the rest of the Middle East. The re-assumption of ministerial and Cabinet control over policy in Palestine was neither swift nor smooth. Ministers relied heavily on the opinions of their permanent staff, especially when they themselves were new and often ephemeral incumbents. Baldwin's leadership in Cabinet was weak, collective responsibility sadly lacking. Baldwin took little interest in foreign affairs, and believed that Ministers should run their own Departments, with himself on hand to settle disputes or give advice. 1 If during 1935-36 the Cabinet dithered for months over its attitude to Italy, it could not be expected to re-assert swift control over a troubled colony. Government machinery for dealing with Arabian and Middle Eastern problems generally still showed a remarkable lack of unified direction. Apart from the traditional, major, but rather obscure divisions between the responsibilities of on the one hand, the Foreign Office and, on the other, of the India Office and the Government of India in the Arabian Peninsula and the Persian Gulf, policy in Iraq (until its official independence in 1932), Transjordan and Palestine was the responsibility of the Colonial Office.2 Defence policy in the Middle East had been placed in the hands of the Air Ministry during Churchill's tenure at the Colonial Office in 1921, but the despatch of troops in considerable numbers to Palestine in 1936 led to an ad hoc assumption of general command by the G.O.C. of the Army. The Admiralty was concerned for its part with the Suez Canal, the Red Sea and Persian Gulf Ports as stop-offs on the Imperial route to India and as terminal ports for oil supplies.

As a result of sustained economic growth over the past few decades, new formal groups based on specific economic interests have been formed in Lebanon. These organizations which represent developing social and political forces, have become substantially involved in the politics of the town of Zahlah, the setting of this study. The purpose of this paper is to describe and to analyze the political relationships between one type of formal economic interest group, the syndicates of owners of small businesses, and the balance of the political structure: the government, established political leaders, other formal economic interest organizations, and the society in general. Evidence will be presented which indicates that in the context of the town of Zahlah, the relationship between these syndicates, whose membership stems mostly from the middle and lower middle strata, and the established political leadership and other economic interest groups, which are dominated by the upper stratum, is characterized by strain and at times overt, but mild antagonism. Their conflict is based on competition for political following in the town of Zahlah and on the basic question of how the total economic pie is to be divided. However, in spite of this antagonism, the syndicates have found it necessary to seek the often reluctant support and co-operation of these upper strata in order to realise particular political goals. This process will be described first through an examination of the syndicates and their relations with other segments of the society and second through two extended examples which will indicate how the syndicates functioned in two separate kinds of situations: a regional issue which in theory does not impair the interests of any of Zahlah's strata and another issue which is specifically related to the economic interests of small businessmen. Most studies on politics in Lebanon usually pass over or ignore the activities of the organized economic interest groups in favour of a concentration on the more established political forces: the president and the cabinet, members of parliament, religious divisions, and political parties of the left and right. An important aspect of this study then is its focus on these relatively new groups and their developing role in the social and political structure in contrast to the prevailing emphasis on the more established political forces. Consequently, this paper is an attempt to open new ground and in the process will probably leave more questions unanswered than it answers.

High-capacity pulse code modulation (PCM) transmission systems have made little impact despite the availability of suitable technology and the rapid growth of low-capacity systems. It is shown that high-capacity systems can now be introduced into toll telephony networks without short-term economic or compatibility disadvantages and with considerable long-term advantages. A 120Mbits/s coaxial cable system compatible with 12-MHz systems is described in outline.

In 1965 in an article entitled 'Appeasement: the Rise of a Revisionist School', Donald Watt drew attention to the need for a much closer investigation of the actual, rather than the formal, functioning of the British foreign policy-making apparatus during the 1930s. Instead of a simple analysis going no further than the personalities and prejudices of a handful of principal characters he suggested that consideration should be given to such wider phenomena as the breakdown of both parliamentary and cabinet government, the power of the senior civil servants, the nature and expression of public opinion, and the loss of faith in democratic processes. Mr Watt also referred to 'Professor Arthur Furnia's somewhat

The delta modulation (DM) of signals which are already in digital form is of interest in a variety of signal-processing applications. It is shown that a delta modulator for digital inputs may be usefully interpreted as a process of slope bias, accumulation, and overflow detection leading to designs which are simpler than those based on analog techniques. Applications are discussed including a divider for delta-modulated signals and an averager of K delta-modulated inputs.

When a grating is viewed by scanning electron microscopy, a moire pattern is observed. Applications of the moire phenomenon in scanning‐electron‐beam lithography and microscopy are discussed, including adjustment of the spatial period and angle of a scan raster, analysis of distortion in a scan raster, analysis of stray‐field beam deflection and measurement errors, and registration of a scan field relative to coded patterns on a substrate.

For the first two years of the war the French government drew up no programme of its war aims. When the cabinet began to consider its aims in Europe during the summer of 1916, it still avoided serious discussion of war aims overseas. Faced with the overwhelming preoccupations of the Western Front, the government paid little heed to the future of the Empire. Such war aims as France possessed outside Europe by the time of the armistice were arrived at in two ways: first, byad hocagreenebts with her allies in the Middle East and in West Africa, agreements forced on the government by the course of the war; secondly, by acommission d'étudeestablished in 1918 to prepare for the peace conference, a commission from which ministers were excluded. The colonial war aims that emerged in these two separate ways were the product not of the French cabinet but of theparti colonialand its sympathizers within the foreign and colonial ministries.

Incoherent optical image processing operations that facilitate interpretation and data reduction are discussed. They are based on spatial pulse coding and quantization of density levels and of spatial frequency distributions, averaged over areal sampling cells.

Eine Methode zur Herstellung von Rohrvervielfacher-Rastern durch Stapelung von gerillten Glasplattchen wird beschrieben. Resultate und Moglichkeiten des Verfahrens werden diskutiert.

This paper describes an interactive system-COLUMBUS-for the development of well-structured programs in assembly language, Cobol, and PL/I. One of the basic concepts employed is the use of Nassi/Shneiderman charts as the unique reference document. For specifying the control structures of a program, the programmer uses a set of control primitives which are common for all languages used. Data declarations and executable statements are taken from the individual language. This mixture is called the COLUMBUS source form. From this source form Nassi/Shneiderman diagrams and cross-reference matrices can be produced in a language-independent fashion; pure source for the individual languages is produced by a set of preprocessors in a language-dependent fashion. This paper illustrates the mechanisms involved by giving some small examples for the individual languages, and it also gives a brief history of the project and reports on quantitative and qualitative results obtained so far. The plans for future extensions are also explained.

The object of British policy before 1939 was the maintenance of British independence, an object which determined her policy towards Nazi Germany. Since Britain could not create enough military strength to defend herself against a German-controlled Europe, she had to persuade Germany or, failing that, compel her not to dominate Europe. Domination over eastern Europe must be prevented, because the result would be domination over western Europe. Of course, British governments wished the UK to be prosperous, wished to preserve parliamentary democracy, the capitalist system and the other manifestations of western liberalism. But British policy aimed to secure these things without sacrificing British independence, which was most dangerously threatened by Germany. The way in which and the methods by which this policy was pursued depended on the armed strength of the United Kingdom, which depended on the economic resources thought to be available for rearmament. These resources were not enough to make the United Kingdom safe against Germany; hence the protracted British attempts to make a bargain with Germany a bargain which the British had always intended should contain an agreed limitation on armaments. Failing such a bargain, British independence must rest on its allies, a fact which might itself compromise that independence. The limitations on British strength were most clearly defined, in terms of the money available for arms expenditure, by an inquiry conducted under the chairmanship of Sir Thomas Inskip, the Minister for Co-ordination of Defence, after Chamberlain had become Prime Minister in 1937. He reported to the Cabinet at the end of 1937 that

A new method of speech digitization called residual encoding is introduced, and its application to the speech digitization problem is studied. The residual encoding system is a form of differential pulse code modulation which utilizes both an adaptive quantizer and an adaptive predictor. The residual encoder differs from previous systems in two ways. First, a sequential estimation method is used to continuously update the predictor coefficients, and second, the predictor coefficients are not transmitted, but are extracted from the estimate of the speech signal at both the transmitter and receiver. No form of pitch extraction is employed. The residual encoding system with a Kalman filter or a stochastic approximation algorithm for identifying the predictor coefficients has produced good quality speech at a data rate of 16 kbit/s.

It will be seen from the error calculations that the absolute error of the moire indirect method for measuring the television-raster nonlinearity coefficient is more than four times smaller as compared with the error obtained in measuring Kn by means of the test chart 0249 method. The systematic error in measuring Kn by means of the moire method can be neglected, since it is within the range of several hundred ths of one percent.

This paper reports on CAGES, a programming system which substantially simplifies the process of writing interactive graphics application programs for use in a distributed processing, satellite-host configuration. It allows programs written in a PL/I subset to be configurable: program modules . (main program, subroutines) and data can be easily reassigned from the host to the satellite, or vice versa. That is, the division of labor between the two computers is readily modified.The CAGES system supplements the operating system services normally provided on the host or satellite computers by providing the illusion that the application is executing in a single computer memory with dual CPUs. In reality the application is distributed between the memories of the host and satellite computers. To maintain this illusion CAGES provides three types of services:Inter-computer subroutine CALLs and RETURNs. A subroutine call executed on one computer and targeted to a subroutine resident on the other computer is known as a remote procedure call. It is supported just as one would expect. A message containing the subroutine's name and parameters is sent to the computer where the subroutine is to be executed. Following its execution, a message containing results (modified parameters) is sent back, and the calling routine continues its execution.(2) Inter-computer CONDITIONs. A SIGNAL statement or interrupts on one computer raising a CONDITION for which there is an enabled ON-BLOCK in the other computer is much like a parameterless remote procedure call. It is supported in essentially the same manner as a remote calls.(3) GLOBAL data references. Variables with EXTERNAL scope which may be referenced from subroutines in both computers are known as GLOBAL variables. If, when referenced, a GLOBAL variable is not located in the memory of the referencing computer, the reference is said to be a remote reference.The CAGES system handles such references by obtaining the needed data from the remote computer and placing a local copy of it in the memory of the referencing computer. The program is then allowed to access this copy.Figure 1 illustrates the over-all structure of CAGES. Application programs are written as if they were going to be resident on only one computer. The programmer then adds extended declarations specifying GLOBAL variables and the desired configuration of the application program. These declarations and the source code are input to the CAGES preprocessor. The preprocessor slightly changes the declarations of the GLOBAL variables in the source code, generates some additional procedures, and outputs three files. One file contains procedures destined for the host (IBM 360/75), one contains procedures destined for the satellite (PDP-11/45), and one contains symbol table entries for GLOBAL variables. The (modified) source procedures are then compiled by either the PL/I-F compiler (host procedures) or the PLCD[1,2] compiler (satellite procedures). Finally, the link-editors of each computer combine CAGES run-time routines with the object modules produced by the previous compile steps to produce two executable load modules,one for each computer. Although the implementation at U.N.C. is based on PL/I, other languages which can be compiled for both host and satellite could be used with this approach.It should be clear that CAGES is not a graphics package in the usual sense. Indeed, any graphics subroutines or other graphics support used by the application program appears to the CAGES system as part of the application, as figure 2 shows. Thus CAGES does not require or provide for any particular type of graphic data structure. In fact, the CAGES system is equally useful to non-graphics programs which must for some reason be distributed in the memories of a two computer network.

We consider a transform coding system that uses a lower-triangular transformation to uncorrelate the data. Based on this transformation we propose a generalized differential pulse code modulation (DPCM) system and show that at high bit rates it performs almost as well as coding by the method of principal components (Karhunen-Loeve transformation). This study connects the transform coding system to the DPCM encoder by showing that the proposed system simplifies to a standard DPCM encoder for Markov data.

A tunable matched filter for the major PCM codes has been synthesized utilizing a developmental bucket-brigade delay (BBD) line. The variable delay feature of the BBD allows continuous tuning of the matched filter over a wide range of bit rates. By combining and weighting the outputs of two BBD lines, matched filters for nonreturn-to-zero (NRZ), return-to-zero (RZ), and biphase codes are realized with a signal-to-noise performance within 0.8 dB of theoretical.

Theoretical results are presented on probability of error in the detection of binary FM signals for various frequency deviations with fixed bit rate, restricted predetection filter bandwidth, ideal limiterdiscriminator reception, and integrate-and-dump postdetection filter decision. The results show that suboptimal system performance can be achieved by choosing the largest possible value of deviation index which lies approximately at 0.7 + 2n, where n = 0, 1,...,k. k is determined by the reconstructability of signal after the bandpass filter.

The possibility is shown of accounting for vacancy ordering in ABx nonstoichiometric compounds in the cluster-component model. The example of monoxide titanium is considered.

The calculations of Huang and Reiss for the power spectrum of a pulse code modulation message is here extended, corrected, and generalized to include a formalism for an arbitrary Markovian process. The formalism contains arbitrary pulse shape and transmission times. For a first-order Markovian message the importance of the quasidiscrete frequencies is emphasized and it is concluded that these frequencies are more significant in defining the necessary bandwidth for transmission than any “optimized” choice of transmission times.

This concise paper describes experiments with a television source encoder which consists of a differential PCM encoder followed by entropy coding. This encoder converts analog television signals into a digital bit stream for digital transmission or storage. When optimized, this type of system is known to perform very close to the rate distortion bound. The differential PCM encoder has a 16-level quantizer during low entropy areas of the picture (quiet areas) but switches to a 6-level quantizer in high entropy (busy) areas of the picture which tend to fill up the buffer. This strategy avoids buffer overflow and has the desirable property that it produces low noise in quiet areas of the picture and higher noise in busy areas of the picture.

To perform mathematical operations on data available as graphic recordings, an apparatus has been developed for the recovery of analogue signals from the recording itself. This device, based on repetitive optical reflection scanning, is capable of simultaneously processing up to eight curves drawn on the same chart. The useful operating area is 27 cm*45 cm, but simple modifications can be introduced to treat strip chart recordings. The electronics used for data conversion are partly digital and use sampling techniques. Special provisions have been introduced to minimize noise problems during the trace detection process. Traces down to 0.5 mm in width are easily detected and the overall accuracy is better than 1 mm.

As a general rule, treaties of alliance, as between all forms of political organization, continue for only so long as they remain compatible with the perceived interests of the participants. The six-hundred-years-old alliance1 between Britain and Portugal has proved to be no exception. In the more recent past British policy makers the Foreign Office, the Cabinet and the Service Departments have been particularly keen to scrutinize and reassess the Portuguese connection in terms of the United Kingdom's own perceived strategic and commercial interests. The alliance had endured, even in the twentieth century, precisely because it has continued to serve those interests, in return for which successive British Governments have upheld their promise to guarantee, albeit reservedly, the integrity of Portugal and her empire. At the same time it would be incorrect to assume that discussion amongst British policy makers on the subject of the alliance has produced complete agreement. An examination of the official discussion within the period 1910-45 reveals a number of divergent views concerning the Portuguese connection. Even the possibility of terminating the alliance was discussed on occasions and sometimes received the approbation of members of the policy making bodies. Within the period under review the first occasion upon which a full discussion occurred on the subject of the alliance was in late 1912. Winston Churchill, First Lord of the Admiralty, and Prince Louis Battenburg, First Sea Lord, were both convinced that Spain was more important from the military and strategic point of view than Portugal; and the Anglo-Portuguese Alliance was hardly compatible with good relations with Spain given the animosity that existed between the two Iberian countries.2 As a result, the Admiralty War Staff, largely influenced by Churchill, drew up a memorandum which was critical to

This paper describes CAPS, a simulation system which enables an analyst without programming experience to quickly produce (in hours) guaranteed executable programs through the use of an interactive dialog. The result is a substantial reduction in both time and effort from the point of problem definition to the availability of model output for decision making. CAPS was developed by Dr. A. T. Clementson of the University of Birmingham and this paper draws heavily upon his work. (See Ref. 1) The user dialog with CAPS is described and examples of the ease of use are given, including an actual model.

A study of combining two ways of reducing the redundancy in the digital representation of speech signals is presented. Differential pulse-code modulation (DPCM) encodes the signal into digital form and reduces the redundancy due to correlation in adjacent sample values of the signal. Following this DPCM operation, entropy coding is used to reduce redundancy due to the unequal probabilities of the DPCM quantizer levels to be transmitted. Theoretical studies agree with Computer simalation results with real speech signals. The concepts of sliding entropy and sliding signal to quantizing noise (S/N) ratio are developed to measure the way in which the entropy and S/N ratio vary with time during a speech utterance. Plots of these quantities versus time for four different utterances are shown. Both adaptive and nonadaptive quantizers are studied. And both uniform and minimum mean-square error quantizing rules are included. Buffer length requirements are calculated for the entropy coders.

The student of contemporary history is quite commonly aware of the extraordinary degree to which our opinions on the recent past are riddled by myths which, by frequent repetition, have become cosily familiar home truths. It is not surprising to find contemporary political observers, working from severely limited information, guess work and prejudice, getting things wrong. However, it is somewhat discomfiting to find these versions in the history books within half a decade, and positively alarming to see them passing from there to our body of Received Truths. I suspect that we think we know much more about the recent past than we in fact do. To come to the point of this article. It would, I think, be generally agreed that on March 30-31, 1939, Chamberlain's Cabinet panicked at news of an impending attack on Poland, and hastily, without time to reflect, extended to her a guarantee against German aggression. And it would be very widely agreed that this Cabinet because of an abhorrence of Bolshevism, and a desire to do a deal with Germany at no stage during 1939 desired an alliance with Soviet Russia, negotiating with that Government not to secure an alliance but rather to appease and dupe public opinion. In this article I will try to show that Chamberlain's Cabinet, during the latter half of March, deliberately chose Poland rather than Russia as Britain's key Eastern European ally, despite the advice of the Chiefs of Staff, but that by late May the appalling consequences of that decision had become sufficiently apparent to have converted the Cabinet to accepting the necessity of alliance with Soviet Russia.

The availability of inexpensive minicomputers and low cost digital/analog conversion equipment enables one to use interactive graphics in situations where such techniques were previously infeasible. The University of Tulsa is presently developing an interactive graphics package entitled BANDMARCH to assist the choreography of marching band drills. The graphics hardward consist of a 32K Interdata Model 70 minicomputer, a 5MB Diablo Disc system, a Tektronix 603 monitor with 256 × 256 point display provided by a pair of Detel 8 bit D/A converters. The program enables a band director who is most likely not computer oriented to prepare a routine in an existing language (About Face, Left Flank) and view the result of his ‘design’ in real time. The obvious interactive features of editing, cataloguing and accessing standard functions must be provided in a way that can be easily understood. T.U.'s BANDMARCH (not an acromym) provides such features. Common data structures in a relatively novel environment are a demonstration of the soundness of these techniques to an interactive graphics situation.

A new method of forming a visual image by ultrasound is described. A shadowgraphic transmission image similar to an X-ray radiograph is produced by the application of a technique known as Time Delay Spectrometry. The system uses a repetitive frequency sweep with a linear relationship between frequency and time and the transmitting and receiving crystal are scanned in raster fashion about the subject. By electronic processing, an image may be built up which represents the energy transmitted through the specimen with a given time delay. An intensity modulated picture encompassing the full shades-of-gray capability of the recording system can be produced. A second type of image showing transmission time through the specimen may also be formed. Brightness changes in the displayed image in this case correspond to changes in the ultrasonic transmission time through the specimen.

A method of measuring the cross-section areas of some structures of the human spinal cord is described for the purpose of obtaining the coordinate values by means of simultaneously photographing the transverse section of the spinal cord, together with a microscopic objective square raster. The obtained coordinate values have been processed by means of a computer and represent the statistical model map of some structures of the human spinal cord. By means of the present method, the classic anatomical and topometrical figure of the spinal cord is converted to a coordinate system that may be defined mathematically.

This paper reports upon the results of tests of the transmission of data over single- and multiple-hop companded delta modulation (DM) systems. The DM coder-decoder (CODEC) was optimized for voice transmission. Modem bit error rate (BER) achievable over the range of 1200-9600 bits/s is presented. A comparison with the performance of pulse code modulation (PCM) is included. The comparison indicates that the two systems are comparable for error-free digital lines but favors the DM system for lines with errors.

Standards for graphics subroutines would encourage the coding of portable programs using graphics. However such standards do not yet exist. In this paper a small set of generally available primitive subroutines, and fortran , are used to pragmatically provide a degree of portability for a second level graphics package. This package consists of only nine subroutines and yet provides considerable power for coding interactive graphical numerically oriented programs.

A discrete receiver structure is introduced that consolidates the problems of bit detection and bit synchronization to provide optimal estimates of bit values without explicit knowledge of the transition epoch. Equations are developed for the propagation of the discrete a posteriori density function on an interval-by-interval basis. The general model is developed for a signal corrupted by additive and multiplicative noise, and the receiver structure is shown to be equivalent to a synchronous discrete receiver. The model is applied to on-off-keyed (OOK) modulation in the presence of multipath.

We consider optimum uniform data quantization for noisy channels. We present a general formulation for natural encoding that results in simple expressions for the mean-square error. Specifically, we show that the optimum location of the center of the quantizer is at the mean of the distribution for all error rates. The optimum levels for quantization and the corresponding mean-square error are presented for Gaussian and uniform data. For the latter the width of the optimum quantizer for noisy channels is shown to be smaller than the entire range of probability distribution.

At the outbreak of war in August 1914, the Germans poured out propaganda in the form of posters, leaflets and pamphlets, in an attempt to explain Germany's entry into the war and discredit the motives of the allies. The British government was greatly disturbed by the virulence of the German campaign, which was specially directed towards influencing the United States of America. At the end of August 1914, the matter was raised in the cabinet: ‘Mr Lloyd George urged the importance of setting on foot an organization to inform and influence public opinion abroad and to confute German mis-statements and sophistries.’ On 5 September the cabinet decided that steps were to be taken without delay to counteract the dissemination by Germany of false news abroad. Though there had been no peace-time precedent, the cabinet accepted the need for an organization to co-ordinate propaganda directed at foreign opinion for the duration of the war.

Three whole pots and sherds of thirteen other vases from early Late Helladic IIIC contexts at the site of Korakou are identified as non-Mycenaean on the grounds of fabric, shape, decoration, and surface treatment. It is argued that, although being alien to Mycenaean ceramics, these pieces were nevertheless manufactured locally. They are thus taken to be evidence of an intrusive population element whose ultimate origin is to be sought in Bulgaria or possibly Rumania, where the intrusive pottery has its closest published affinities in material of earlier date. Discoveries of comparable non-Mycenaean pottery in roughly contemporary contexts at the other southern Greek sites of Lefkandi, Perati, Athens, and Mycenae suggest that the presence of northern intruders at Korakou may be more than a local phenomenon. The close correspondence between certain classes of the intrusive Korakou pottery and particular wares found at Troy only in the VIIb i and 2 settlements points towards a parallel situation at Troy where one or more new population elements probably settled following the destruction of Troy VIIa. Connection of the intruders with disturbances in southern Greece at the end of LH IIIB and with the destruction of Troy VIIa is possible, but far from certain. No reliable estimate of the numbers of the intruders can be made on the basis of evidence at present available. During the course of his excavations at Korakou in 1915 and 1916, the late C.W. Blegen found a number of sherds belonging to distinctively manufactured vases in the later Mycenaean levels which he uncovered. From these sherds, three more or less complete vases were restored, which were illustrated in Blegen's final publication of the site.2 A number of sherds from similarly manufactured vessels and roughly contemporary contexts were not published, and it is the primary aim of this article to describe and illustrate in its entirety this small group of vases and sherds as it is now preserved in the storerooms of the Corinth Museum. All of the vases represented in this group are handmade and have a burnished surface. The term "burnished" is used here to describe a lustrous surface on which the marks of a burnishing tool are clearly visible. These marks vary from broad and shallow grooves to mere thin lustrous lines on the vase surface. They all represent the application of a 1 This article is essentially an excerpt from my doctoral dissertation, The Late Helladic HIIB and IIIC Periods at Korakou and Gonia in the Corinthia (Department of Classical Archaeology, University of Pennsylvania 1974), copies of which are available in the libraries of the University of Pennsylvania and of the American School of Classical Studies in Athens, as well as via microfilm from University Microfilms, Inc. of Ann Arbor, Michigan. I am greatly indebted to Mr. C.K. Williams, II, for the permission both to study and to publish the Late Helladic IIIB and IIIC material from Korakou now stored in the Corinth Museum. I would like to thank Sarah H. Rutter for the drawings, Marcia Langer for the photographs pl. I, figs. 1-4, and the firm of Ioannidou and Bartzioti for the photographs pls. 1-3, figs. 5-17. I am grateful to Dr. M. Langdon, Mr. S. Diamant, Miss K.D. Vitelli, Mr. M.R. Popham, and Mr. Williams for reading this manuscript and for making many helpful suggestions and criticisms. The following abbreviations will be used: Babadag S. Morintz, "Quelques problemes concernant la periode ancienne du Halstatt au Bas-Danube 'a la lumiere des fouilles de Babadag," Dacia NS 8 (1964) IoI-I8. FS Furumark Shape Korakou C.W. Blegen, Korakou (Concord 1921). Lefandi M. Popham and E. Milburn, "The Late Helladic IIIC Pottery of Xeropolis (Lefkandi), A Summary," BSA 66 (1971) 333-49. MP A. Furumark, The Mycenaean Pottery, Analysis and Classification (Stockholm 1941). Porto Perone F.G. Lo Porto, "Leporano (Apulia). La stazione protostorica di Porto Perone," NSc VIII, 17 (1963) 280-380. Saturo F.G. Lo Porto, "Satyrion (Taranto). Scavi e ricerche nel luogo del pih antico insediamento laconico in Puglia," NSc VIII, 18 (1964) 177-279. Thasos Ch. Koukouli-Chrysanthaki, "Proistoriki Thasos," ArchEph (1970) Chronika 16-22. Troy IV C.W. Blegen, C.G. Boulter, J.L. Caskey, and M. Rawson, Troy IV (Princeton 1958). 2 Korakou, figs. Io04:1-2 and 105. This content downloaded from 157.55.39.29 on Tue, 07 Jun 2016 05:39:11 UTC All use subject to http://about.jstor.org/terms 18 JEREMY B. RUTTER [AJA 79 tool to the leather-hard surface of the vase, an action which has brought up the finer particles of clay to the vessel surface before firing and which results in a lustrous vessel surface after firing. The nature of the tool, the number of times it is rubbed against the vase surface, the pressure which is applied to it, and the consistency and composition of the unfired clay will largely determine the kind of burnishing mark which appears on the fired vase. Virtually all of the vases and sherds to be considered are products of coarse clays containing large amounts of mineral inclusions ranging up to four millimeters in diameter. A final characteristic of these pieces is their color, generally red, brown, or gray.3 This ceramic group is clearly distinguishable from the rest of Late Helladic (hereafter, LH) III pottery. The latter includes a number of distinct fabrics, none of which is at all comparable to the handmade and burnished material. Almost all fine Mycenaean pottery is made on the wheel from wellcleaned clay and is invariably light in color.4 A range of miniature handmade shapes in this fabric may be children's toys." A somewhat coarser clay, more porous when fired and known as "oatmeal" fabric due to the addition of a large amount of dark grits and the resultant bumpy texture of the fired vessel surfaces, is used to make large closed storage vessels such as amphoras, hydrias, and jugs, as well as occasional large open vases like kraters and basins. Again, the vases in this fabric are invariably wheelmade with light-colored surfaces where unpainted. The clay of standard Mycenaean cooking vessels has been sand-tempered to improve its resistance to heat stress. When fired, the fabric tends to be dark in color, but the vases in it are still wheelmade and their surfaces are never lustrous.' Pithoi, vats, tubs, larnakes, and other large vessels are made in a series of less standardized fabrics. Although such fabrics contain a large number of non-plastic inclusions, they are often light colored and are never burnished. The LH III handmade and burnished pottery from Korakou consists of:7 I. Hole-mouthed Jar (ill. i; pl. I, fig. i). CP 337. House K, level II. D.rim (variable) 0.13. Max.d. o.I68. D.base 0.126. H. 0o.150-0o.158. Full profile ! ..? ? ",.(.:. , _ ,, .:.. '. . '"" ". " 'ii!::: ' '??.. .?..:?,~~~~~ ..~~~.:.. ?... ... ?:;:?.:... :'t.. "" '" 2?~ .?f~b ?o"