Task analysis: the missing link in software development methodologies

Systems development methods or software methodologies have evolved considerably over the past few years. This development has tended to fall into two main areas: Software Engineering and Human Computer Interaction (HCI). The two main techniques proposed in Software Engineering were Structured Analysis, as proposed by Ross and DeMarco; and Semantic Modelling. These two different approaches were later combined to yield Modern Structured Analysis, in which Structured Analysis was augmented with data modelling techniques. Modern Structured Analysis was subsequently replaced by Object Oriented Analysis and Design (OOAD) which adopted a holistic approach to data and processes, encapsulating them into objects. In the HCI domain, design methods such as Hierarchical Task Analysis (HTA) and Task Analysis for Knowledge Descriptions (TAKD), have long been used to model the cognitive nature of the tasks performed by the users. Recent work by Walsh, Um, Long and Sutcliffe have proposed combining Task Analysis (TA) with Structured Analysis and Design methods, in order to improve system usability. Analysis for Task Object Modelling (ATOM), as proposed by Walsh, is an example of such a method which combines TA with object modelling in an integrated life cycle approach. This article will review the major Software Engineering methods, together with the principal HCI methods and motivate for the integration of the two areas on the basis of improved system usability. A taxonomy of software development methods as proposed by Blum will be reviewed and a proposal made to augment the framework to include the issue of user-centered design methods. The extended framework will then be used to classify several of the principal software design methodologies, together with the principal HCI methods. Each of these methodologies will be reviewed and conclusions drawn as to the efficacy of each in the context of the software life cycle. We will demonstrate that all of the traditional design methodologies fail to include Task Analysis (TA). An alternative methodology, Analysis for Task Object Modelling, as proposed by Walsh, will be discussed, which includes TA with object modelling. We will motivate that TA is an essential part of Requirements Analysis and HCI design. Furthermore, failure to include TA may result in serious usability problems. Methods like ATOM, which combine TA with OOAD, are thus the most applicable software methodologies for designing usable systems in the future. Further research, however, is needed to improve and integrate the conceptual modelling techniques in ATOM

Studies on the histopathology and pathogenesis of Newcastle disease of fowls in South Africa, with special reference to the lymphoid tissue. A preliminary report.

1. Newcastle Disease, after intramuscular inoculation of virulent virus, was characterised by pathognomonic lesions in the spleen, the gastro-intestinal tract, and the nervous system. 2. In the Spleen degenerative changes in the cells of the lymphoid sheath were noted in early deaths. In some of them flake-like granules were observed. There were depletion of lymphocytic cells in the follicle, increase in the number of plasmacytes, and proliferation of reticulum cells. In cases with a more protracted course, hyperplasia of the lymphoid tissue was apparent. 3. In the gastro-intestinal tract the chief changes were observed in the Proventriculus, the Small Intestine, and Caecal Tonsils. In early cases, this was of the nature of a localised necrosis with haemorrhage. The changes in the lymphoid tissue were of a similar nature as those observed in the spleen. 4. The Nervous system in the majority of cases revealed a hyperaemia, and in some, small haemorrhages. The changes in the small blood vessels were of the nature of a so-called "endotheliosis" with an infiltration of the walls with lymphocytes, and other cells of the blood. In some of these vessels the presence of plasma, mononuclears and red cells was noted within the lumen. In some cases chromatolysis and slight gliosis were seen. 5. More information is desired about the depots, morphology, and function of the lymphoid tissue of the fowl. It would, however, appear that lymphocytes and plasmacytes have an independent origin, and that they are probably implicated in the propagation of the virus and antibody mechanism. At this stage it is not possible to indicate what the nature is of the flake-like granules in some of the cells of the lymphoid tissue. Further investigations are indicated to clarify some of the problems raised in this preliminary study.The articles have been scanned in colour with a HP Scanjet 5590; 300dpi. Adobe Acrobat XI Pro was used to OCR the text and also for the merging and conversion to the final presentation PDF-format

The psychological selection profile for civil-military coordination officers in peace-support operations: The results of field research in the Sudan

The introduction of a multidimensional approach towards peace missions in complex emergencies emphasises the importance of coordination between the military and humanitarian components at all levels of interaction. Cooperation and coordination between the military and humanitarian components are critical in achieving a common goal for these operations: to alleviate suffering and prevent loss of life. The challenge of finding suitable personnel who can develop, enhance and sustain effective working relationships and overcome the potential for conflict in civil-military coordination, has not been addressed in practice and research. The military needs to identify personnel who, firstly, conform to the generic psychological peacekeeping profile and secondly, portray the knowledge, skills, and abilities to perform the coordination function satisfactorily. Due to the absence of a psychological selection profile for civil-military coordination officers, the selection and screening of competent military personnel members remain a challenge. Through this descriptive field research (conducted in the Sudan), a psychological selection profile for civil-military coordination officers is developed and defined. The theoretical foundation and primary data from field research are integrated into a job competency model for civil-military coordination officers, useful for future selection purposes. The results of this research are presented as a model of provisional selection criteria for civil-military coordination officers. Preliminary predictor and criterion data were collected to describe the relationship between selection measures and performance ratings of job incumbents. Areas for further research are discussed. Are these events indicative of a militarised SADC strategic culture as opposed to the declared pacifist preferences to resolve conflicts

Pathological studies on neoplasms of dogs in South Africa

In 1956 studies on neoplasms of dogs were commenced at the Liesbeek Clinic. De Kock (1957a) stressed the importance of these investigations, especially in respect of their comparative value to the study of neoplasms in man. Suitable forms were circulated amongst veterinarians and these were based on the observations published in a number of overseas journals. In such a survey of tumours in dogs in South Africa, special attention should be paid to geographical, breed, age, sex and site incidences, as well as to clinical data. The importance of careful autopsies was stressed for a proper reorientation of the site and nature of the tumour and the problem of metastasis, and the possible occurrence of multiple primary tumours. It entailed the proper selection of specimens and suitable smears for microscopical studies in order to arrive at a histological diagnosis. Large numbers of tumours in dogs have been investigated and described, e.g. by Feldman (1932), Jackson (1936), Innes (1943), Mulligan (1949), and others. Head (1959) and Cotchin (1959) have so far investigated close on 9,000 tumours in dogs. Jackson indicates that a full history of the subject, and a careful description of the specimen in situ are of great importance to the pathologist. Innes maintains that unless meticulous autopsies with histological examination are made on a long series of animals, many tumours may evade recognition or accurate diagnosis. The effective classification of neoplasms, according to Jackson, is one of the most subtle problems of pathology. There is a multiplication of nomenclature on the basis of variation of morphological appearance. He maintains that proliferative processes may be variously classed as nodular hyperplasia or as an adenoma in such organs as the liver, spleen, prostate, etc., and difficulties also arise in deciding whether one is dealing with a benign or a malignant tumour. Further comment on certain aspects of the pathology of tumours raised in the literature will be referred to when the results of the investigations at the Liesbeek Clinic are considered.The articles have been scanned in colour with a HP Scanjet 5590; 600dpi. Adobe Acrobat XI Pro was used to OCR the text and also for the merging and conversion to the final presentation PDF-format.The National Cancer Association of South Afric

Studies on the lesions and pathogenesis of East Coast fever (Theileria parva infection) in cattle, with special reference to the lymphoid tissue

1. Regressive changes in the lymphoid tissue appeared to be the striking pathological feature in cattle that died of East Coast fever. 2. The earliest stages of Theileria parva seemed to occur mainly in the immature lymphocytic cells. The developing stages of the schizonts brought about a disintegration of most of the lymphocytic cells and the nodules lost their identity. The meshes of the reticulum, and the dilated subcapsular and medullary sinuses showed the presence of infected and disintegrated lymphocytic cells and dislodged schizonts, as well as a certain amount of fibrin, oedema, debris of cells, and infrequently, macrophages. 3. During the last stages of the disease, the impression smears of the lymphoid tissue showed practically all the lymphocytic cells infected with schizonts, chiefly gamonts. Due to the overlapping of the agamogenous and gamogenous cycles, it was not possible to say how long each cycle lasted, or how frequently it was repeated. 4. The damaged lymphocytic cells were apparently eliminated by a process of dissolution, whereas phagocytosis did not seem to play a significant part. 5. Schizonts, carried away in the circulation, probably infected lymphoid tissue, or newly-formed aggregates of lymphocytic cells in other parts of the body. The merozoites, during the last stages of the disease, were frequently present in large numbers in the impression smears of the spleen. It was, therefore, possible that many erythrocytes might have become infected in the ted pulp of the spleen. 6. Regular and often extensive aggregates of lymphocytic cells appeared as a secondary involvement in the kidneys, liver, adrenals, etc., and less frequently and less extensively in such organs as the lungs, myocardium, skeletal muscle, pancreas, hypophysis and thyroid. The central nervous system was not involved in these cases. 7. These secondary aggregates of lymphocytic cells were found associated with the walls of the blood vessels, of the bile-ducts or of the bronchi, or bronchioles. They were lodged in a reticulum, and mitosis was not infrequent. These newly formed lymphocytic cells became infected with schizonts and disintegrated, in the same way as described in the lymph nodes. 8. It seemed doubtful whether these infected and damaged lymphocytic cells present in the circulation, were able to emigrate and proliferate to form aggregates in the so-called secondary localities. 9. There appeared to be a "potential stem cell" widely distributed throughout the body, which under stimulation could proliferate to produce cells found on the lymphoid tissue. It would, therefore, seem to be more likely that "stem cells" in various parts of the body were stimulated to form aggregates of lymphocytic cells in situ. 10. The elimination of the lymphocytic cells, in the primary lymphoid depots, probably led to a compensatory formation of these cells in other parts of the body. 11. From the brief discussion of a number of papers dealing with the function of the lymphoid tissue, it was possible that in the extensive dissolution of lymphocytic cells in East Coast fever, a vital function in the animal body was interfered with. This apparently was an important contributory factor to the rapid wasting, the emaciation, and the subsequent death of the animal. 12. At present it is not understood how the many infected erythrocytes at the peak of infection were eliminated in the body.The articles have been scanned in colour with a HP Scanjet 5590; 300dpi. Adobe Acrobat XI Pro was used to OCR the text and also for the merging and conversion to the final presentation PDF-format

Determining the radial distribution function of water using electron scattering: A key to solution phase chemistry

High energy electron scattering of liquid water (H2O) at near-ambient temperature and pressure was performed in a transmission electron microscope (TEM) to determine the radial distribution of water, which provides information on intra- and intermolecular spatial correlations. A recently developed environmental liquid cell enables formation of a stable water layer, the thickness of which is readily controlled by pressure and flow rate adjustments of a humid air stream passing between two silicon nitride (Si3N4) membranes. The analysis of the scattering data is adapted from the x-ray methodology to account for multiple scattering in the H2O:Si3N4 sandwich layer. For the H2O layer, we obtain oxygen–oxygen (O–O) and oxygen–hydrogen (O–H) peaks at 2.84 Å and 1.83 Å, respectively, in good agreement with values in the literature. This demonstrates the potential of our approach toward future studies of water-based physics and chemistry in TEMs or electron probes of structural dynamics

Bioclimatological studies on white rats in South Africa. No 1. Skin cancer in rats following continued exposure to sunlight

1. Skin cancer in rats (and in mice) can be produced by exposing them daily for definite periods to ultraviolet light. 2. Roffo produced identical neoplasms in rats by exposing them daily for 5 hours to sunlight. This was confirmed in the experiments at Onderstepoort, where rats were daily exposed for 4.5 hours to sunlight. In one instance a new growth developed in a rat exposed daily for only 2.5 hours. 3. So far no spontaneous skin cancer have been observed in the rats at Onderstepoort when kept under sheltered conditions but in one rat in these experiments, a fibroblastic sarcoma was found in the liver, lung, and omentum. 4. The skin cancers occurred on the hairless parts of the skin, and in the majority of rats new growths appeared in more than one place on the body. The ears were most frequently affected. 5. There was no definite occurrence of metastasis into other organs. 6. The earliest appearance of a new growth, to which attention is drawn, was ±10 months after exposure of the rats to sunlight. 7. In all the new growths a microscopical diagnosis of an epidermoid carcinoma was made. The statement by Roffo that some of these neoplasms were of the nature of sarcoma could not be confirmed at Onderstepoort. 8. The earlier lesions revealed the usual characteristics of an acanthoma associated in some cases with hyperkeratosis, while in the large actively growing neoplasms there was much evidence of anaplasia.The articles have been scanned in colour with a HP Scanjet 5590; 300dpi. Adobe Acrobat XI Pro was used to OCR the text and also for the merging and conversion to the final presentation PDF-format

Dr P.J. du Toit : an appreciation

Retirement of Dr. P.J. du Toit as Director of Veterinary Services, Department of Agriculture, and as Dean of the Faculty of Veterinary Science, University of Pretoria, Union of South Africa.The articles have been scanned in colour with a HP Scanjet 5590; 300dpi. Adobe Acrobat XI Pro was used to OCR the text and also for the merging and conversion to the final presentation PDF-format

Studies on tuberculosis in dogs, and on a case of human tuberculosis contracted from a dog

1. Apparently this is the first case on record in which tuberculosis of the skin in man was contracted from an infected dog through a wound. The infection probably occurred when handling the heavily infected lymph nodes and serous membranes of dog No. I at post-mortem. 2. In view of the rather obscure nature of the lesions, and the fact that this case was complicated with nervous distemper, tuberculosis was not suspected in this dog, until diagnosed histologically. 3. The nodule on the finger, which remained completely circumscribed, was successfully excised approximately three months after infection. 4. In the two dogs with natural tuberculosis the infection was of the nature of an incomplete primary complex in the abdominal cavity. 5. Although large doses of tubercle bacilli were injected into two; dogs intravenously, the disease was much milder, and less widespread than in the two natural cases. 6. In all the dogs clusters of macrophages and epithelioids dominated the picture in the lesions, whereas neutrophiles appeared to play an insignificant part. There was no evidence of Langhans giant cells and calcification, and in the liver, spleen and lungs no caseation was observed. 7. In view of the morphology of the tubercle bacilli, the nature of their growth in culture media, and of their behaviour in rabbits, it was concluded that the human type of organism was involved in all these cases.The articles have been scanned in colour with a HP Scanjet 5590; 300dpi. Adobe Acrobat XI Pro was used to OCR the text and also for the merging and conversion to the final presentation PDF-format