Investigation and modification of the inversed vortex phase field method for phase unwrapping

Поступила: 12.07.2021. Принята в печать: 05.08.2021.Received: 12.07.2021. Accepted: 05.08.2021.Предложена модификация метода встречного вихревого поля для развертывания фазы при интерферометрической обработке данных космических радиолокаторов с синтезированной апертурой. Модификация включает в себя выделение и развертывание низкочастотной фазы, получение интерферограммы остаточной фазы и ее фильтровую обработку. Произведена оценка точности получаемых при помощи алгоритма цифровых моделей рельефа на примере интерферометрической обработки радиолокационных данных ALOS PALSAR с использованием эталонных высотных данных. Произведено сравнение точности с другими распространенными алгоритмами развертывания фазы.The paper focuses on the problem of the phase unwrapping in spaceborne remote-sensing interferometric synthesized aperture radar (InSAR) systems. Major unwrapping methods and techniques are considered and the modification of the inversed vortex phase field method of phase unwrapping for interferometric data processing of space-borne synthesized aperture radars is proposed. The modification includes the separation and unwrapping of the low-frequency phase only, and obtaining of the residual phase interferogram, which phase range does not exceed 1–2 ambiguity height values. This approach significantly reduces the number of phase residues and increases the processing speed. The other modification implies filter processing of the residual phase without phase unwrapping, which includes iterative separation of the low-frequency using the Gaussian filter and phase subtraction. This approach moves phase fringes to the relief inflection areas, and is similar to the minimum-cost flow unwrapping results. The computational complexity of the algorithm is proportional to the interferogram size and the number of the phase residues of the lowfrequency phase interferogram. The accuracy of digital elevation models obtained by the algorithm was estimated using the ALOS PALSAR radar data and the reference altitude data. The results show, that the accuracy is compared with the minimum-cost flow method, but has less computational complexity

The Long-term Loneliness of Widowhood: A Systematic Review of Marital Status Differences

Loneliness can be prominent in bereavement, possibly leading to compromised mental and physical health. We systematically reviewed the extent of loneliness across marital status groups, examining the prevalence, intensity, risk factors, and correlates of loneliness in widowhood, compared to other marital statuses. Studies that met predefined criteria as well as investigated marital status (comparisons) were included in the review. For reporting, we followed the PRISMA statement. Thirty-eight studies were included. Widowhood was associated with a greater likelihood and intensity of loneliness when compared to other marital statuses, and especially the divorced. Widowers were on average lonelier than widows. Findings suggest that , widowed persons are uniquely vulnerable to loneliness, and that, in the long-term, loneliness may be more pronounced among the widowed than the divorced. However, methodological shortcomings (e.g., heterogenous samples, different measures of loneliness) of available studies must be considered, and future research should aim to overcome these limitations

Cremation and Grief:Are Ways of Commemorating the Dead Related to Adjustment Over Time?

Funeral services are known to serve multiple functions for bereaved persons. There is also a common, intuitively reasonable assumption of positive associations between engaging in funeral activities and adjustment to bereavement. We examined whether restricting ceremonial cremation arrangements to a minimum has a negative association with grief over time. Bereaved persons in the United Kingdom completed questionnaires 2 to 5 months postloss and again a year later (N = 233 with complete data; dropout = 11.4%). Neither type nor elaborateness of the cremation service, nor satisfaction with arrangements (typically high), emerged as significantly related to grief; no major subgroup differences (e.g., according to income level) were found. Results suggested that it does not matter to grief whether a more minimalistic or elaborate funeral ceremony was observed. We concluded that the funeral industry represented in this investigation is offering bereaved people the range of choices regarding cremation arrangements to meet their needs. Limits to generalizability are discussed

Grief counseling efficacy : Have we learned enough?

Henk Schut responds to Larson and Hoyt's challenge (see Bereavement Care 28 (3), winter 2009) to the prevailing pessimism about the effectiveness of grief counselling. Studies indeed show that the more formalised professional therapeutic interventions with those experiencing complicated grief reactions can be effective, but for those who have simply lost a loved one, the evidence suggests that counselling is unlikely to be effective unless the individual feels they need help, and so actively seeks it. This article summarises the evidence and goes on to argue that we are unlikely to achieve more lasting outcomes with those considered at risk of complicated or prolonged grief until we are able accurately to pinpoint what the risk factors are, and target our interventions accordingly