Qualitative Analysis What it is

Transcription

1 VISUAL DATA

2 Qualitative Analysis What it is Types of Qualitative Data Textual Visual Document Narrative Observational Field Notes Diaries, letters, etc. Interview trancript Photographs Video Qualitative analysis is the process of interpreting such data collected during the course of (qualitative) research

3 Analysis of Visual Data How? A method to get qualitative information from a happening is by a visual observation. This can be done by making direct observation (observational field notes), photographs, video. Direct observation : Less dependent on visual equipment Heavily rely on observer (visual) memorizing capability More suitable for a static to very slow happening Photographs : Depend on visual equipment and visualization technique Heavily rely on visual quality of captured image (spatial resolution) Suitable for a static happening Set of photographs less dynamic happening

4 Analysis of Visual Data How? Video : Depend on visual equipment and visualization technique Heavily rely on visual quality of captured video image (spatial and temporal resolution) Suitable for a dynamic happening

5 Analysis of Visual Data LLS Technique Particle Seeding System Particles type Physical Properties Dimethyl Silicone Oil (Toshiba, TSF ) = 50 mm 2 /s ; = g/ml ; T boil = 300 o C Seeding generator Droplets diameter Number density Particles slippage Light source Laser sheet Atomizer (nebulizer) type Less than 2 m About 400 particles/cm 3 Less than 0.15 mm/s Laser Light Sheet (LLS) 4W- Ar + laser (Coherent Innova) Thickness, t = 0.4 mm Camera Recording Exposure Digitizing Image Resolution Visualization High speed video camera 1000 frame/s 1/2000 s (shutter speed) AV master video capture 480 x 640 (.avi format) 280 dpi Laser sheet intensity Varied no more than 3% from peak at center (within assessment region)

6 Analysis of Visual Data LLS Technique Main airflow Test section Slot width Step height c.s = 50x80 mm 2 length = 300 mm 1 mm 20 mm Laser source Settling chamber PC + interface Contraction nozzle Monitor y Reflector Lens arrangement z l f x Exhaust Video player Video camera Seeded nitrogen gas

7 Analysis of Visual Data An analysis of visual data generally comprises of two parts (no need to be sequentially stated) : Descriptive part Interpretation part Key questions for analysis : Descriptive part : What is the (spatial, temporal, conditional) setting of the image? What is the main subject of the image? Does it include other elements than main subject? Interpretation part : What is the main activity/happening of the (subject of) image? Does there seem to be any trend/pattern/theme to a set of photographs (sequence of video images)?

8 Analysis of Visual Data Example 1

9 Analysis of Visual Data Example 1 Another set of images in Fig. 3.4(b) shows that in the case of injection with I = 0.04 and 0.1, the jet trajectory is highly deflected toward the upstream, and cannot sustain its growth too far. The jet trajectory breaks up soon and the gas distributes rather uniformly in the recirculation zone. This result suggests that the injected gas mixes rapidly with the recirculating airflow and without deep penetration, which might be attributed to the domination of strong turbulence and high reverse velocity of flow near the injection port. Meanwhile, a more extensive growth of the injected gas jet which penetrates through the shear layer can be observed in the case of I = 0.3. Mostly, the trajectory deflects downstream, indicating that it penetrates up to the region where the free stream comes into effect.

10 Analysis of Visual Data Example 2

11 Analysis of Visual Data Example 2 Fig show the fractograph under different sintering temperature. The STS 316 nanopowder necking was formed at 800 C, and rapidly growth at 900 C. The lower necking formation and growth of nanopowder is due to higher surface area. Secondary phase was observed under Scanning Electron Microscope (SEM) as globular particle. It was found above 1000 C. This particle will reduce the ductility of sintered part with poor bonding strength with austenite matrix. This particle sizes was increase and was joined each other with sintering temperature. It indicates that secondary particle has higher melting point than STS 316.

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13 Exercise of Visual Analysis 1

14 Exercise of Visual Analysis 2

15 Exercise of Visual Analysis 3

16 Exercise of Visual Analysis 4

17 Suggested Analysis - 1

18 Suggested Analysis - 2

19 Suggested Analysis - 3

20 Suggested Analysis - 4

21 Suggested Analysis

22 Photographer s s response to suggested analysis