Science topics: Projection
Science topic

Projection - Science topic

A defense mechanism, operating unconsciously, whereby that which is emotionally unacceptable in the self is rejected and attributed (projected) to others.
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I want to reproject ERA5-Land data from orthogonal projection to 9km Ease-Grid v2 in MATLAB or R. Any leads are much appreciated. Thanks in advance.
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You can use griddata/scatteredinterpolant function in MATLAB.
Use reference 09km EASE v2 grid LAT and LON from SMAP L3_SM_P_E to convert E5-Land into Ease v2 grid.
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I am trying to downscale GCM-(CanCM4) data to bhima basin catchment(finer scale) for projecting future scenarios. Further I have used following variables ta,ua,zg,va(all these @ 925,850,700,200 pressure levels) and pr,psl(total 6 variables). I am attaching image which I got from working on GCM, now considering mid point of these GCM grid points only 2 station lie on periphery(+ mark) for down scaling. Can I downscale these GCM points to the 0.5deg  grid points? If yes, how to consider the weights?
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This is a good question.
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Hello Maxent Community,
I have been generating SDM models and projections in Maxent. I have had some success with one set of variables (some Hydroshed variables mixed with World CLIM variables); however, I am having a bit of trouble with a model based solely on World CLIM variables.
I used a Peasron correlation matrix to select eight World CLIM variables, which model well with my species' occurrence data. The issue arises, when I ask Maxent to project on future World CLIM variables - the returned projection is almost entirely blue. There are a few specs of red and yellow (indicating prediction probabilities), but the vast majority of the projection is blue (indicating zero prediction probability). I tried rerunning the model with clamping turned off, but the problem persisted.
I am relatively novice with Maxent, so I was wondering if I am overlooking a setting that may help correct this issue. I am a bit confused, because when I ran the projection with the Hydroshed variables and some of the same World CLIM variables, the future projection looked just fine. Any advice or suggestions would be tremendously appreciated.
Thank you in advance for your help!
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I recommend reading this article:
Predicting the impacts of climate change on the distribution of species: Are bioclimate envelope models useful?
Best wishes
Bekhruz
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At the Monte Carlo casino, I saw an unusual advertising image. It rotated around a vertical axis and seemed suspended in the air; there was no screen behind it. The image was bright and colorful. Who knows how it works or has an idea how such a visual effect can be obtained?
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Приветствую Вас, Анатолий Смолович.
1.Обратил внимание на Ваш вопрос по причине того, что пару лет ранее один студент рассказал мне о подобном способе демонстрации объемных изображений (в парах какого-то вещества?)...
2. Просмотрите сайт https://impremium.ru/blog/image-air/
3. В своей деятельности продвигаю идеи более широкого использования преимуществ цифровой оптоэлектроники и ИС с оптическими связями, др. (см. данные моего профиля, еще - публикации по направлению д.т.н, проф. Шустова М.А., РФ).
С уважением, доцент Проскурин Н.П., к.т.н., НУЗП, Украина.
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Creating interpolating polynomial on the unit circle by projecting the zeros of certain polynomials vertically on the unit circle as well as reading their convergence behaviour for the functions analytic inside the unit circle can how be seen for the application part in the real life.
Where such type of interpolation can be applied to view a much wider perspective to such type of research problems.
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see
Orthogonality, interpolation and quadratures on the unit circle and the interval
Ruymán Cruz-Barroso, Pablo González-Vera, Francisco Perdomo-PíoJournal:Journal of Computational and Applied MathematicsYear:2010
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What is MODIS's default Geographic Coordinate System and projected coordinate system? My study area is Bangladesh. I found the image distorted (the upper portion is bent towards left and lower portion is bent to the right. Pics attached). How can I project them to Geographic Coordinate System: WGS 1984 and projected coordinate system: WGS 1984 UTM Zone 45N ?
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Mr. Aqil Tariq is correct. Please open the MODIS product in Arc Map 10.8, and search projection, and add projection and zone and then select output path, and click Ok. Thank you.
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I have a WorldView 3 image with multispectral (only 8 bands, Coastal, Blue, Green, Yellow, Red, Rededge, NIR1, NIR2) and panchromatic band. I can open one of them (either multispectral or panchromatic) without any problem in ENVI 5.4. But when I open both images in a single ENVI window, both multispectral and panchromatic bands get distorted (looks like both are projected to a different coordinate system). Both images are in Geographic coordinate system- GCS_WGS_1984, Datum- D_WGS_1984. Can anyone help me to fix this problem?
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We have also faced pixel shift issues in Worldview-3 Pan and Multispectral images
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I have programmed a method for solving quadratic optimization problems under linear constraints, this method is depends on the projection of a point onto a convex polyhedron in R^n, so I have programmed Dykstra's successive projection method and adapted it in my method, but Dykstra's successive projection algorithm dosen't work well, it's spend a lot of time even days to find a projection in 3 dimention real space!!!, I don't know if his algorithm is slow or I haven't programmed it properly!!! I have spend a lot of time on this method, so I'm very pluseur if somone can guide me to another projection method that I can get the algorithm code ready.
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It’s my PhD project to build a new method can solve those problems faster than those exist methods
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I am interested in commercially available liquid crystal displays for use as a spatial light modulator in a custom-designed video projector. Where can I buy such LCDs?
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I want to convert projection of a co-ordinate from UTM to transverse mercator of specified location. I have false easting, false northing, central meridian, scale factor value of this location. How can I do this?
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If you don't want to do the maths, you could use software. For a single coordinate, the free Tatuk Coordinate Calculator is good: https://www.tatukgis.com/Products/Coordinate-Calculator/Description.aspx
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I am doing a hydraulic modelling in SMS software. I have downloaded a georeferenced satellite image from USGS earth explorer website. I opened both the satellite image and scatter data in SMS and made same projection for each. But, they were in different location with different co-ordinate as shown in picture below. How can I fix this issue?
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Dear Shahidul,
If you are using ArcGIS for mapping, try to change or define projection.
Type in search "define projection"
Or "project raster".
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Chern Connection on a Finsler manifold.
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Thank you. It's very useful.
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How do you understand the entity known as the devil or satan in some religious traditions? Do you think the devil is a being with a life of its/his/her own, or a projection of the evil forces in the human psyche and in the universe, as some others have suggested? What do you think? What documented sources of support have you got? Thank you.
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Hello,
The concept of Satan has different explanations in religious traditions.In the Islamic tradition, Satan was an archangel who refused to accept the superiority of Adam so that when God asked the angles to kneel down and respect Adam, Satan refused and asked God to be given time for alluring the sons of Adam off the rectified path, which the servants of God were supposed to follow. I agree with the second option where you say devil exits as a projection of evil desires in human psyche.I hope that the following links can provide you with the answers you are looking for.
Best regards,
R. Biria
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I am building a model to see how climate change can affect crop yield. climate and crop yield are connected through the Hargreaves evapotranspiration equation. How can I express this equation in continuous form? It is reasonable to express the variation in daily mean temperature as a percentage of the variation in global mean temperature? 
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Dear Ruggiero;
I have fully read your model structure. I think you need to have a review on your model.
The first thing which I should notice is your first model:
Yi=ai*ET-bi
It's really a simple linear trend, no thing more. We have some stronger model for relationship of evapotranspiration - or maybe crop water - and yield. I send you one of the best "Crop yield response to water" which is prepared by FAO. I suggest you to read to read chapter 2 from page 6 to page 13.
The second is your evapotranspiration model which you named that as Hargreaves and Merkley. I think you used their book "Irrigation Fundamental", but the equation in page 71, which you use that for you model is originally the Hargreaves and Samani equation, which is presented in "Estimation of potential evapotranspiration" [1] which calculate potential evapotranspiration, not reference evapotranspiration. The method is a Radiation-Temperature Based method, and I should notice you that we have so different kind of methods to estimate potential evapotranspiration which are Temperature Based, Mass Transfer Based, Radiation Based and etc. If you want to use each one of theme I hope to be able to help you.
The last thing is your model, which is a growth model that change with time. I think you should have a review on your model!!
anyway, If you want to project climate change impacts on yield, you should notice other parameters that change too; for this I suggest you to read APSIM reference manual:
And now, as an answer to your question, I should tell you that the climate projection in cordex project could project lots of parameters including potential evaporation which is being calculated using FAO Penman-Monteith equation in a fine spatial resolution and daily temporal.
Hope It helps.
Regards
Tabatabaei
[1]Hargreaves, G. H., & Samani, Z. A. (1982). Estimating potential evapotranspiration. Journal of the Irrigation and Drainage Division, 108(3), 225-230.
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There is a theorem stated as, Let k be a real closed field and D subset of k be a subring of k. Given a semi-algebraic set of kn+1 defined over D, its projection to kn is a semi-algebraic set defined over D. Can some one please explain what does this mean, and if possible how to visualize this geometrically
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The theorem in question is due to Tarski-Seidenberg. Suppose you have a finite disjunction of conjunctions of polynomial equalities and inequalities in $k^{n+1}$
$$ S(x_1,\ldots, x_n, x_{n+1}) \. $$
The projection to $k^n$ would be given by
$$ \exists x_{n+1}: S(x1,\ldots, x_{n+1}) \; .$$
As Peter Breuer comments, this would correspond to an infinite disjunction of algebraic formulas.  However, it is possible to "eliminate the existence quantor", i.e. to find an equivalent finite disjunction of formulas. For the proof of this elimination one needs an algebraic expression of the coefficients of a polynomial of one variable (the variable which vanishes by projection) that allows to decide whether the polynomial has a zero.  A  sturm chain provides such a device and is used in the proof you'll find e.g. in
The calculations are algorithmic, I can't conceive of an easy visualisation. But it might help to have a look at Coste's examples.
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Ie similar to the BioClim data kindly provided at WorldClim by Hijmans et al, 2005
I am doing some SDM modelling combining the BioClim dataset with N-deposition variables 
-Ideally 30arcsec (~1km) resolution .tif's
-Ideally timepoint calculated around 2003 and projections for 2050 or 2070
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I'm working with SMOS data to validate soil moisture at 70 stations, for an entire state.
To start the comparisons, I need to know how many stations are concentrated in each SMOS pixel, however, I'm having some trouble generating the Grid of the satellite in GIS software because of the image projection (EASE2).
Could someone indicate a way to do this?
Thanks for any help you can provide.
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Hello Diego Araujoo 
Pls go through this link. I hope this will help in importing your data in GIS
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Researchers should have knowledge about mortality projections, risk or a wider scope of looking at mortality risk
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Don't know about your project but if you are talking about mortality at the population level and have some long term mortality reates data, you can test for trends over time and for changes in trend related to a particular intervention. Best wishes
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A simpler way to get climate model projections or a resource that explains how to get data from CMIP5 in more detail would be much appreciated.
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If you would like I can send you by e-mail a csv file with  temperature values projected for a certain point  in Africa from CORDEX simulations at 0.44 degree resolution. 
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I want to know how one can make a infinite complex projective space into (naturally of course) a kahler manifold. in fact i'm trying yo undersand natural kahlerian structure of a arbitrary infinite complex projectice space/
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    Dear Erfan,
    When you say infinite dimensional projective space, I suppose you are thinking in an infinite projective manifold. Thus you need to look for a preserving a Hermitian metric assoicated to a symplectic structure. One clear example of that is the Fubini-Study metric. There are generalizations using Grassmannians One natural generalization of CPn is provided by the Hermitian symmetric spaces of compact type, such as Grassmannians.
    One good reference for going deeper is:
   A. Moroianu, Lectures on Kahler Geometry, London Mathematical Society Texts, 69. Cambridge University Press (2007)
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For example, suppose in an image, there is a rectangular wall of which four of its corners are clearly visible, this would form a plane which looks like a trapezoid when viewed from an oblique angle.
From the image, the four points in 2-D space can be obtained with respect to the frame. How could you calculate the angle between the wall and the line of projection from the camera?
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You may be able to use vanishing points/line for your purpose. The two pairs of parallel lines on the wall determine the vanishing points/line. Have a read at this file which may be useful.
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I take it that values (moral value, aesthetic value, etc.) are only knowable by ostensive definition (viz. by direct experience with the types of properties that any particular value is understood to be a token of). Now if true, I think that it is a mistake to suppose that they are merely the residue of the subjective states that they purport to be an experience of (a mere 'projection', as Mackie seems to suppose). Is it not equally true that 'objectivity' might be also coextensive with a property being "there in the world" even though the scale by which we measure it is a human construct? In other words, although the world does not come 'pre-sliced' into evaluative schemes, does it not still objectively 'answer' to the evaluative predicates we apply to it?
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To Lilliana's question, I'd say "not necessarily", though I'd not want to exclude the possibility that thee are some things that are common to values of all types.
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I am stuck with problem to determine the structure of quotient M/K , K is abelian Lie group, non-compact, M is R^n with removed finite numbers of linear subspaces, the question is wether or not M/K is smooth manifold. I think better is to use general theorem than trying to show directly that M/K is smooth manifold (maybe I am getting lazy), there is analogy with complex or projective spaces, these manifolds are quotients of Lie group action, we can prove directly they are manifolds, but instead of we can apply theorem, and I need such theorem, please help. Action of K is linear, so orbits are linear subspaces, but not all of them are of maximall dimension (and these have to be removed).
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It looks to me that you need further conditions about  the action to obtain a smooth quotient. Why the quotiente is a hausdorff  space?
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Galton (1868) famously described great variation between individuals regarding the vividness with which retrieved visual memories of scenes are typically re-visualized, ranging between "as vivid as perceptual experiencing" and no discernable imagery at all. Seashore's early research revealed similar individual variation regarding vividness of recalled (audiated) imagery for musical sounds, and moreover concluded that the characteristic level of vividness for an individual does not appear to be enhanceable by short-term or prolonged ear-training regimes. Vividness implies both fidelity or completeness of detailed feature-representation and intensity or loudness of recalled  images. While I know from my own experimentation with various intensive ear-training tactics that the timbral richness and clarity of temporal onset of retrieved imagery can be much increased thereby, my findings bear out Seashore's regarding loudness - adult individuals have a permanently fixed personal ceiling level that is not affected by the content of the imagery.
The brain's encoding of imagery loudness seems to be poorly understood and not extensively researched. Neural firing-rate in primary auditory cortex (A1) has been shown to co-vary with loudness of sound-stimulus, and Penfield et al's famed experiments with electrical stimulation of exposed A1 surfaces in awake surgery-patients evoked auditory imagery at life-like levels. A1, however, does not appear to store encoded representations of loudness, and I would presume higher, cognitive levels to be accountable for that. However, there would also be factors concerning modulation of cortical activation/arousal-level by midbrain nuclei projections to consider - and I guess the question of what neural substrates actually determine imagery-loudness boils down to identifying which of those modulatory projections cause the most impact on experienced loudness when artificially stimulated or suppressed. Would anyone reading be able to supply me with any researched information on that, please?
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Dear Richard
My area is Biolinguistics and my work involes how to establish  that there is a Faculty of Language, a virtual organ (see my RG details) in the Brain, Since music involves speech, I am sure that here too the Faculty of Language is involved. In fact, in Hindu mythology, the Goddess of Learnig, Sarasvathi, is also the Goddess of Music!
As with any Human faculty, (or with many disease) music also will be influenced by three factors
1. Inherited, 2. Intra-Uterine/Congenital 3. Post natal.
As with speech and Language, exposure to music during childhood must also be important. Part of inherited effect may be that the child is exposed earlier. And, however much a Human being has a well developed Faculty of Language, he/she will never speak unless exposed to speech! It must be so with music too?
As regards Auditory image, it might be impossible to say exactly which stimulus results in an image that can be recalled.
There is a famous Lullaby in Malayalam, written 300 or more years ago. When ever I hear it, I don't know why, I remember my mother. May be she must have sung it to me who was her firstborn, but I don't remember her singing to me actually! This must be what you mean by auditory image, isn't it so?
Studying this is tough. May be you can find people who does have similar auditory images and study their cortical/neural/ activity by EEG, PET scan, etc., afeter exposing them to image recalling and non-recalling sounds.
Narayanan
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On each closed manifold (orientable and nonorientable) there is non-trivial continuous involution. Is that true or not? Positive response is known for two-dimensional manifolds and real projective spaces.
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Dear Rogier!
Thanks!
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Hi All,
         I am working on structured light 3D camera. My main objective is to make Fast/Accurate structured light 3D camera by using commonly used projector.the main problem i usually faced during this process is to synchronize he camera with the projector. I want to expose the camera when pattern projection starts. This kind of synchronization is quite hard to achieve. How we can do this ? 
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Muhammad,
Common, commercial video projectors are tricky - it's rather difficult to synchronize them. After several tests, I made such a system, PC-driven bu Matlab, by choosing to make it work slower but avoiding the recording of camera frames during which the Gray code projected changes, and which are incorrect. I did it 1) by introducing a delay between the transmission of a pattern to the projector, and 2) by recording for each projected frame 2, even 3 camera frames - which also allows coping with the correct regime of the camera !
I hope it helps !
Dan
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I need the liquidus projection for the Ni-Ti-Zr system, and I could only find a partial liquidus projection in the composition region of 0 to 50 at.% Ni.
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Dear Marcia,
You will find it on:
Go to Figure 4 in the article.
Regards
Alberto
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We consider M_{2}(C) as a  8 dimensional manifold with a natural Riemannian metric. The space of projections in M_{2}(C), all A with A=A*=A^{2}, is  a two dimensional submanifold homeomorphic to S^{2}.  We denote it by M. Is $M$ a round sphere, that is with constant curvature?(We restrict the metric of M_{2}(C) to M).
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OK, Ali. So your environment is in fact R8 with the metric given by its euclidian norm sqrt( sum of xi2 ) . Let a matrix be (zz2  ;  zz4 ). Your set lies in an intersection of hyperplanes, which are Im z= Im z4 = 0 , Re z+ Re z4= 2, Re z2 = Re z3, Im z+ Im z= 0. Those are exactly 5 independent affine hyperplanes (prove independence by rank computation!), and their intersection is an  affine space T  of real dimension 8 - 5 = 3. On the other side the euclidian norm of R8 computed for points of your set is sqrt([ (1-z)2 + (1 + z)+ 2x2+ 2y] / 4 ) = sqrt ( [1 + x2 + y2 + z2 ] / 2 ) = 1 because (x, y, z) in S2 as embedded in R3. So your set (call it S) is the intersection of a 3-dimensional linear space T with the sphere S7 canonically embedded in R, and the euclidian distance in R8 generates (the same) metric on T. For me it is clear: your sphere is round, constant curvature, and canonically embedded. However, the affine space T does not contain 0 in R8 so the center of our sphere, which lies in T, is not 0 from R8. This center and the radius of the sphere, as sphere embedded in T, must be computed. As a result, we will see that the sphere has not curvature 1. It will have a different oneI
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Problem of finding the minimum distance from a point to the complement of a convex set is a non-convex problem. Its solution set (the set of all projections) is not a singleton in general. There have been some algorithms for finding the projection onto a convex set. But in the reverse convex case, such as, projection onto the complement of an Ellipsoid, I don't know any algorithm to find a point in the set of projections.
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This is a good question with lots of possible answers.
A good place to start in looking for an answer to this question is
See Section 2, starting on page 3, for the mathematical framework (the intersection of convex sets' complements are introduced in Remark 2.2).   Projections onto closed convex cones are introduced in Section 1, page 3.
The boundary of a convex set and boundary of the complement of a convex set are considered relative to projections in
U. Eckhardt, W. Scherl, Z. Yu, Representation of plane curves by means of descriptors in Hough space:
See Chapter 9 (Reconstructon), starting on page 20.
A strange as it may seem, a good place to look in considering this question is in the projection onto coconvex (complement of a convex set) in terms of sequences of automorphisms.    This is done in
K.-U. Bux, Finiteness properties of soluble arithmetic groups over global function fields, Geometry and Topology 8, 2004, 611-644:
See Chapter 6 (The Moufang Property), starting on page 628.
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we haven't a microscope projection to do it
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Remember that the diameter of a wool fibre can change significantly depending on the relative humidity as wool fibres swell when they absorb moisture. That is why commercial wool testing laboratories measure fibre diameter after a period of 'conditioning' at 20 degrees celsius and 65% relative humidity. For consistent measurements it is important to ensure that the environment in which you are measuring the samples, does not vary too much in temperature or humidity - particularly if you are measuring a large number of samples over a period of days or weeks. If this is the case, it may be necessary to select a number of 'control' samples (n = 5) of various diameters and measure these at both the start and end of each day and use any changes over time to 'correct' your measurements for variation in environmental conditions.
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As I read literature projecting contradictory views with profound theories and research, I am a bit perplexed and indecisive. One of the theories underscore the art of projection.
Looking forward to your views and suggestions.    
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Explaining the purpose of the research helps to recruit participants through their interest in a subject which quite often allows subsequent snowballing recruitment.  It also supports thoughtful responses because they feel they belong to something rather than adjunct to it.  To address issues of bias, having space for comment under each question lets participants clarify their responses if the options available to them would otherwise not adequately reflect the answers they would like to give.
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The "piercing subspace" problem may be stated as follows:
There are given several subspaces in a projective space, rather non-intersecting.
Find an additional subspace of a prescribed dimension that has intersections of prescribed dimensions with each of the given subspaces. Determine how many solutions are there.
I believe this problem was popular many years ago. Can you suggest where to find the best results related to this problem?
The simplest example of this type of problems is the line piercing three skew lines in a 3d space. This problem does have infinite number of solutions. When the additional line is to intersect four lines then in real spaces there may be two, one double or none solutions while in complex spaces there are two solutions or one double. A theorem related to this is so called sixteen-point theorem.
Can you suggest some other theorems of this type and how to find them?
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Srinivasan, I asked a question about subspaces of projective space, not of vector spaces. Projective spaces are spaces of rays of vector spaces. A point of a projective space is a one-dimensional subspace of a vector space. Check somewhere the definition of a projective space. 
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Investigating/Assessing the criminal tendencies in an Individual.
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Thanks, Naeem. I don't think any of the tools listed are of use for interrogation officers. No test we have in mental health can provide sufficient positive or negative predictive power to be meaningful in terms of evaluating guilt to innocence see for instance (see for instance Steve Hart's very valuable reflection on these issues, downloadable from SFU at http://www.sfu.ca/psyc/faculty/hart/Hart,_SFU_Website/Publications_files/Hart,%202004-2011,%20EAPL,%20Complexity,%20uncertainty,%20and%20risk%20assessment.pdf. )
There are some tools that have been developed to assist police or probation make decisions regarding future risk, such as the ODARA in relation to spousal abuse. Tools mentioned above such as the LSI are valuable for convicted populations to help evaluate risk and target interventions. There are likely to be major ethical issues with using psychological assessment tools for interrogation purposes. 
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Does the projection of a vector $X$ in $\mathbb{R}^k$ onto a closed convex cone (positively homogenous set) $C$ in $\mathbb{R}^k$ with respect to a positve definite projection matrix $V$ always exist? i.e.
$\inf_{w\in C}\left(X-w\right)^TV\left(X-w\right)=\min_{w\in C}\left(X-w\right)^TV\left(X-w\right)$
Specifically I am interested in cone $C$ with linear constraints over its elements (of course these must not violate the properties of a cone).
Many thanks
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Since I like nice expositions, I would more often prefer the older ones, as the modern ones tend to be very technical. This is to some degree by necessity, but the balance between exposition and technical arguments now more often is lost, with a too strong focus on the technical development, and too little energy is put on constructing links between subjects, illustrations of results and their utilization. Further, I find that more often books today lack enough good graphical illustrations, examples, and good basic as well as advanced exercises (with answers/hints). I think this is because too often a book is written based on a series of very good technical papers, and the author tends to forget that a book should have a very different style of writing than a technical paper.
Among the best books in terms of style, layout, and sheer reading pleasure, are:
1. Lasdon - Optimization Theory for Large Systems. Classical, and focusing on problems and algorithms for large-scale problems and how to iteratively turn them into problems that are manageable so that the original problem can be solved after some coordinating steps.
2. Bazaraa, Sherali, Shetty - Nonlinear Optimization. The layout in the first edition, 1979, I think, is much nicer than the later ones from 1993 and 2005 (or is it 2006?). The layout matters a lot to me, by the way.
3. Bertsekas - Nonlinear Programming. There is a new edition every few years. Very good, accessible and nicely structured. 
These three are frequently used in beginner PhD courses on nonlinear optimization. Further books that I like but have not used as much are:
4. Luenberger, Ye - Linear and Nonlinear Programming, 2nd edition. 
5. Mangasarian - Nonlinear Programming. 
These two are somewhat classical - not as complete as the ones above but written in a nice style, also by masters of the field. And by the way all these five books cover more than convex optimization, so I have somehow answered the wrong question. :-) I think a course on nonlinear stuff needs to cover more than the convex case, anyway.