158 research outputs found

    Morphological hit-or-miss transformation for shape recognition

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    In this paper, the morphological hit-or-miss transformation is analyzed for use in the recognition of both perfect shapes and imperfect shapes. Shape recognition is achieved by locating the objects to be recognized within the image. The shape recognition problem is discussed in the following two aspects. First, a theorem is presented in which the hit-or-miss operations employ the structuring elements [thetav]A and [thetav](W [subset of] Ac), instead of using sets A and (W [subset of] Ac). Here A is the boundary of A, and [thetav](Q [subset of] Ac) is the containing A, [thetav]A is the boundary of A, and [thetav](W [subset of] Ac) is the boundary of (W [subset of] Ac). Second, the recognition of imperfect shapes due to indeterminate variation of an object shape is studied here. Our method employs a priori known shape information as a basis for structuring elements and constructs structuring elements which are then used in a hit-or-miss transformation to find the location of the shape to be recognized. Each occurrence of a target shape is represented either by one point or by a small cluster of points within a calculated range according to the associated structuring elements. Finally, we present the hit-or-miss operation without window restrictions as a technique for recognizing both perfect and imperfect shapes, thereby making the method more flexible.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/29148/1/0000190.pd

    Stratigraphic analysis of lake level fluctuations in Lake Ohrid: an integration of high resolution hydro-acoustic data and sediment cores

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    Ancient Lake Ohrid is a steep-sided, oligotrophic, karst lake that was tectonically formed most likely within the Pliocene and often referred to as a hotspot of endemic biodiversity. This study aims on tracing significant lake level fluctuations at Lake Ohrid using high-resolution acoustic data in combination with lithological, geochemical, and chronological information from two sediment cores recovered from sub-aquatic terrace levels at ca. 32 and 60m water depth. According to our data, significant lake level fluctuations with prominent lowstands of ca. 60 and 35m below the present water level occurred during Marine Isotope Stage (MIS) 6 and MIS 5, respectively. The effect of these lowstands on biodiversity in most coastal parts of the lake is negligible, due to only small changes in lake surface area, coastline, and habitat. In contrast, biodiversity in shallower areas was more severely affected due to disconnection of today sublacustrine springs from the main water body. Multichannel seismic data from deeper parts of the lake clearly image several clinoform structures stacked on top of each other. These stacked clinoforms indicate significantly lower lake levels prior to MIS 6 and a stepwise rise of water level with intermittent stillstands since its existence as water-filled body, which might have caused enhanced expansion of endemic species within Lake Ohrid

    Possible earthquake trigger for 6th century mass wasting deposit at Lake Ohrid (Macedonia/Albania)

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    Lake Ohrid shared by the Republics of Albania and Macedonia is formed by a tectonically active graben within the south Balkans and suggested to be the oldest lake in Europe. Several studies have shown that the lake provides a valuable record of climatic and environmental changes and a distal tephrostratigraphic record of volcanic eruptions from Italy. Fault structures identified in seismic data demonstrate that sediments have also the potential to record tectonic activity in the region. Here, we provide an example of linking seismic and sedimentological information with tectonic activity and historical documents. Historical documents indicate that a major earthquake destroyed the city of Lychnidus (today: city of Ohrid) in the early 6th century AD. Multichannel seismic profiles, parametric sediment echosounder profiles, and a 10.08m long sediment record from the western part of the lake indicate a 2m thick mass wasting deposit, which is tentatively correlated with this earthquake. The mass wasting deposit is chronologically well constrained, as it directly overlays the AD472/AD 512 tephra. Moreover, radiocarbon dates and cross correlation with other sediment sequences with similar geochemical characteristics of the Holocene indicate that the mass wasting event took place prior to the onset of the Medieval Warm Period, and is attributed it to one of the known earthquakes in the region in the early 6th century AD

    An open-label, 1-year extension study of the long-term safety and efficacy of once-daily OROS® hydromorphone in patients with chronic cancer pain

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    <p>Abstract</p> <p>Background</p> <p>Opioid analgesics have proven efficacy in the short-term management of chronic cancer pain, but data on their long-term use is more limited. OROS<sup>® </sup>hydromorphone is a controlled-release formulation of oral hydromorphone that may be particularly well suited to long-term management of chronic cancer pain because it provides stable plasma concentrations and consistent analgesia with convenient once-daily dosing. The objective of this study (DO-118X) was to characterise the pain control achieved with long-term repeated dosing of OROS<sup>® </sup>hydromorphone in patients with chronic cancer pain.</p> <p>Methods</p> <p>In this multicentre, phase III, open-label, single treatment, 1-year extension study, OROS<sup>® </sup>hydromorphone was administered to 68 patients with moderate-to-severe chronic cancer pain, who had successfully completed a short-term equivalence study, and whose pain was controlled with a stable dose of medication (≥ 8 mg OROS<sup>® </sup>hydromorphone or equivalent controlled-release morphine). Patients were started on the dose of OROS<sup>® </sup>hydromorphone equivalent to the opioid dose on which they achieved dose-stable pain control in the equivalence study; dose adjustments were made as necessary and breakthrough pain medication was permitted. Efficacy was assessed with the Brief Pain Inventory (BPI) and patient and investigator global evaluations of treatment effectiveness. No formal statistical analysis was done.</p> <p>Results</p> <p>The mean (standard deviation) duration of exposure to study medication was 139 (129.9) days and the mean (standard deviation) average daily consumption of OROS<sup>® </sup>hydromorphone was 43.7 (28.14) mg/day. All scores were maintained at a mild to moderate severity throughout the study; however, BPI scores for pain at its worst, pain at its least, pain on average, pain right now, and pain relief were slightly worsened at end point compared with baseline. Mean BPI pain interference with daily activities and patient and investigator global evaluation scores also remained generally stable. Treatment effectiveness was rated as fair to good throughout the study. The most frequently reported adverse events were nausea (n = 24, 35.3%), constipation (n = 22, 32.4%), and vomiting (n = 15, 22.1%).</p> <p>Conclusion</p> <p>The results of this extension study suggest that long-term repeated dosing with once-daily OROS<sup>® </sup>hydromorphone can be beneficial in the continuing management of persistent, moderate-to-severe cancer pain.</p
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