I hope to return to him shortly. For the vintage sailplanes lovers , you have this very interesting forum in french and german with plenty of walk around and pictures. Very useful. Thank you, Jan, for reminding me of the "Retroplane" site. It is such a beautiful place to be in, not least the background image of the forum!
Here's why I am so interested in that subject: There are few more beautiful views in history of aeronautics than the gull-winged high-performance sailplanes of the s. In this thread, several of us me among them have professed a particularly soft spot for the German Reiher from The nose profile is extremely modern, some versions had laminar-flow wing profiles, others had variable camber wings.
I have ordered the issue, paid for it, and received an automatic email reply. I am now eagerly awaiting a life-sign from Robert himself anyone done business with the Card Model Shop? I seem to need your constant help to overcome my inability to find things. It's becoming downright embarrassing. At least it resulted in two sources for another sailplane model. Thank you, Jan, for your help - again! Sailplanes have a elegance to them over other aircraft. Even the name "sailplane" so smarter.
To glid with the wind in silenceand use the wind like they do. I can watch our Red Tail hawks all day when they seem to hover in one spot scaning the ground far below looking for dinner.
Maybe I'm crazy but for me there is something I don't know what it is about these beautiful large birds and they of course remind me of the sailplanes. Real beauty. Nothing like it anywhere. No idea where all that came from or why. A true treasure trove! Wad Cutter: So true. Many of the period photos are amateur pictures, making history come alive.
Amazing, isn't it? In addtion some 40 foreign types including well-known German classic historical types used in Poland during this period. For each type, there are sometimes more than a dozen photos. All of the post types modeled by GPM and mentioned in this tread are there. Martin, Waddie - I'm so glad you appreciate the beauty of gliders. I'd like to show you a couple of Polish films illustrating this. At the end you will find a contemporary film with the Polish master sailplane pilot Sebastian Kawa, which truly embodies the feelings you express.
However, my fascination is equally or more with the age when gliding only could take place by lots and lots of enthusiasts cooperating, building and repairing most of the winter, lugging heavy gliders up steep mountain slopes most of the summer, to be rewarded with a few minutes in the air at intervals. This could be illustrated with film clips from the U. But since so much of papermodeling has its roots in Poland, and so many paper models of sailplanes depict Polish types, I set down to search for films showing the Polish gliding scene, preferably pre-war.
Watching it, you will get a superb impression of how massive the gliding movement was in the thirties in a country like Poland. Suddenly, the more than 80 types and variants of Polish gliders gets into perspective. Note particularly the mechanized trolley used for freighting the gliders back to the top of the mountain after a landing in the valley below. What impresses me most is the uphill landings by those pilots who managed to keep aloft in the mountain lift areas.
Note also the double lines of people tugging the rubber ropes used to launch the gliders, and the seemingly fantastic lift immediately after take off. Seems like those gliders are in an invisible lift. I never realized slope soaring could induce that much lift! But the two clips in my view do not seem to be from the same era.
Perhaps someone with a better first-hand knowledge of the Polish gliding scene could date these film clips better, or correct me in my suspicion that they may not even be from the same film.
Now, if you feel that watching this wasn't much fun, you should go directly to the last, colored, clip in this post. But since I've found some more vintage Polish clips of historical gliders, I'll include them.
Here's clip No. In the rest of the clip you get a fine row of Polish light aircraft types from the s. At ca starts a film sequence called "Old time soaring in Poland". Still, placing a film camera on the wings of a glider in those days is not a mean feat! VTOL craft, of less interest here. By now yor are probably very tired of looking at grainy olf black-and-white film clips, however interesting they may be from an historical point of view. Do not forget to click on the C.
Since it is high-quality, it is well worth clicking on the YouTube logo in the clip here, to go to the original site and watch it enlarged. My point with these clips, is that I firmly believe the people lugging their gliders up steep mountain slopes in the s had a dream which may not have been possible to realize fully until today. But I also believe that they realized enough of it to last them in their own lifetime. What, in our dreams, is it that we can't fully realize? Only later generations will be able to say.
As it happens I managed to put an "at least after" date on the first film clip in the previous post, one of the two from the film "First start". So we learn that the film must certainly have been at least after , and that it probably is from the Polish gliding centre Bielsko-Biala.
The rather characteristic tower at the top of the ridge can be seen in several of the other clips, too. Three vintage archives The find of this full issue of the Vintage Glider Club News led to a new search to see if other issues of it were available. And - lo and behold! In fact, thanks to the mammoth task undertaken by Peter Redshaw, almost all UK gliding and soaring magazines from to date have been scanned into searchable pdf-files!!!
Even so, the site is a goldmine. Imagine, vintage books on gliding, to be downloaded and viewed on-screen! The people behind the gliding magazine site would very much like to get a tip on how to accomplish this.
They do have a dedicated search engine, which would have been a great help - if it wasn't restricted to members only. But you can still expect a general Google search to turn up results from this archive.
And you can browse it manually, year by year, issue by issue, just like its British counterpart. Wow Leif those are some cool clips! I realy like the Wampir II tailless glider Rich Leif, thanks so much for posting the videos.
I love to fly the vintage birds and I have collected a few. This morning I was flying a Minimoa from Harris Hill and attach a few screen shots. I also like to fly at the Wasserkuppe using my SG and the Weihe. And yes, I am a paper cutter also. Particular thanks to John for showing the Minimoa panel, and sending it to me separately. This is just what I needed for future refining one of the available sailplane paper models I'm fiddling with.
Hope to be able to show you the result later on. I'm getting quite jealous of his being able to time-travel at will and fly from the Wasserkuppe in the s! Perwsyzy Start First start - was made in , and had its premiere in January This is just a couple of years after the coup-like take-over by the communist party. Implementing the social agenda of the party is still a fragile process, and presumably they had a hard time convincing the population of its value.
So this is a propaganda film, of course, promoting the values of collective social responsibility, The plot underlines this in rather simplistic strokes. The young man we have alread identified as the main character, is in fact: …a clever country boy, Tom, who attends the gliding course "Service to Poland. The pilot has been taken ill. A dramatic storm rising threatens to destroy the glider, which turns out to be impossible to secure. Instead, Tom decides to start [how, one wonders - I would have liked to see this scene], and manages to fly the glider to safety at the airport.
By decree from the commander he then immediately is restated to a higher level. Interestingly enough, the film is described as a "hit" by this source. Back to gliders. Notice the name "Junak" painted on the nose of the glider we already have identified as Jastrzab Hawk SP? Junak means "swashbuckler", if Google can be trusted. This name must have been painted on to the glider for the film congenial to the character of the hero?
The prestanda, however, were not so good - pilots called it "the flying axe". On its good side, it was designed with such strength that it was indeed impossible for any pilot to reach a speed above max.
You simply could not get over mph, and it was designed to stand for mph. So, back to "Junak", where else have we, as paper modelers, come across that name? Did the name painted on the nose of the glider in this film actually influence the manufacturers of the trainer Junak? Just a thought, but an interesting one, wouldn't you say? Leif, you caught on quick I knew I would never make it to the Wasserkuppe especially in the '30's but now I can and also visit many other places My favorite flight from the Wasserkuppe is a bungie launch with the SG on the west slope.
I can glide down and pick up lift over a small village and cork-screw my way back up to a couple thousand feet over the field elevation and cruise around a bit. Then set up a very precise pattern because the SG ls lacking spoilers. Sometimes I have to make "S" turns or side slip to bleed off excess altitude, then land. Again I attached a few screen shots, one is from the by standers view point and the other is the pilots view.
John, thanks for inviting us to your s refuge! I'll take your lead, and remain in that decade for a while. Here's an example: These are pp. Below I have attached the original pdf-files of the four pages shown above as illustrations. On these four pages you get a first hand account of the spectacular and unprecedented flight undertaken by Hungarian sailplane designer Lajos Ludwig in the nazi-German context Rotter, at the Olympic games in Germany.
From a paper-modeling point of view, the method used for covering the nose section is worth noting, isn't it - for once the petal method might actually be scale-like! If for nothing else, this would be an excellent reason to design a paper model of this extraordinary sailplane The wingspan is the same, 20m, it has the option to lower its ailerons to change the wing profile for higher lift in thermals, the minimum sink is 0.
The British editors of the article notes the excellent visibility through the large canopy, and the designer himself recounts in two articles on pp.
This article includes an early and good three-view drawing. Writes Rotter himself: The basis of the design was the idea that the speed and gliding performance of sailplanes ought to be increased, and the range of speed and of sinking speed should be extended by making the ailerons adjustable during flight, both for flying in weak thermic currents and for fast flight with good gliding angle.
Also the cage [sic! To comply with these demands the span and weight of the machine had to be increased; the wing loading also had to be raised to a value in conformity with modern airplane types. And less than two weeks later, on August 9th, Rotter undertook his epic flight to Kiel! It was the longest glider flight to a pre-declared goal till that day, and the longest glider flight of any kind undertaken during It is a very dramatic tale, and I for one was spellbound.
But no spiralling, unless absolutely necessary to accumulate height for an anticipated longish spell of no lift ahead. Analyses show that during this flight he managed a quota of time spent in spiralling in relation to flying on course, which wasn't to be surpassed by anyone until well after the war!
Two years later Rotter was elected to be part of the jury which was to select the sailplane to be used at the Olympics which never took place. Contestants were, among others, the Polish Orlik mentioned earlier in this thread and several German sailplanes.
Rotter remained a leading figure within the Hungarian gliding community, but the Nemere was sadly mistreated. No other exemplar was built, and the original never got to be flown again under good conditions.
Instead it was restricted to bungee-cord launches from hills outside Budapest, for which it was unsuitable due to its relatively high weight. In the final stages of the war it was damaged, but rebuilt again afterwards - only to be ultimately destroyed again in without any further explanations given.
My guess - based on the clothing of people involved - is that the film clip is from these few years after the war. Leif, you have posted some very interesting material, please keep it coming. Does the name Cloyd Artman ring a bell? He was an early American glider pioneer who sometimes used a most unusual launch method. Leif and John, thank you very much for the flight into years gone by. The music was the best part I thought and fit the video perfectly.
One day John you will have to give me a few sim lessons. Flying my Cub in there is one thing but a non powered guilder is another. I did try once and it was the best but I couldn't find the up-drafts to stay up.
You become a true mast of the sky this way. If only my Grumman Duck was in there. Thanks guys, wonderful planes and photos. And what a singularly spectacular method to get airborne - but I'm not sure I would have the stomach to try it outside a sim!
Waddie - Glad you appreciate stuff like this. Here's some more, leftovers from the search for more about the Nemere. Mostly sources for those who like it all. It's really something. You've already seen it - it's the one in the last post. The article is a condensed rewrite ffrom the British Sailplane and Glider issue cited previously.
One similar, but unmarked, photo like the above published in previous post. Also contains this piece of useful information: "As a testament to the beauty of the Nemere, Martin Simons chose this design for the cover picture on his book Vintage Sailplane You can download two versions, or pix wide, both in HD. Image above is actual screenshot from my computer, watching the downloaded big-size clip.
Actually the highest quality video I've downloaded ever, all categories. Why aren't all YouTube clips like this? Schempp-Hirth airbrakes are shown to advantage at the end of the flight, so this is a model of the post repairs undertaken on the original.
This model flight took place May , so its a very recent video. A bit shaky at times, but that's what happens, I guess, when you attach a remote mini wide-angle webcam to the tip of a 5m span model flying in hard wind - those wings flex…. Hello Jan, - Bergfalke, that is very good news! Any chance of Roman Seissler introducing these models for us, you think? Leif, all of this information, pictures, descriptions, the like, are extremely interesting!
And I fear if I continue viewing such content, I'll be inspired to build sailplanes - first you post intriguing content on WW2 aviation Thank you very much Leif, if I had to compare you to another member on this forum, or rather, describe what members you manifest essentially in a single body, it would have to be CharlieC - a member who has acquired such a vast knowledge of armor - plus the great charismatic character of D. As they say, "Just keep doin' you". This thread keeps getting better and better.
I am still deeply in love with warbirds, mainly the Spitfire, but the sleek lines of those vintage gliders are something hardly surpassed in motorized airplanes of the time.
And they were civilian. Leif it is great to have you with us! Kind regards, Martin. Johnray, I'm glad to hear your interest in sailplanes has been kindled! Thus it conforms to the recipy for a succesful paper model replica - no need for petal-shaped nose covering simulating a molded area - here the petals are true-to-scale!
Everything is edgy, fabric over steel tube framework, but still well proportioned, and wings very prettily swept slightly forward to enhance the view from the back seat. There is a large transparent canopy, which allows you a good view of the two seats, with all details visible. Worth waiting for!
Another reason is that this was the mainstay of Swedish glider clubs from the mids onwards. When I was growing up, the Bergfalke was synonymous with sailplanes. In Swedish gliding clubs it is still an unspoken tradition that any attempt at the Swedish distance record for gliders should be undertaken in an old Bergfalke.
Otherwise one isn't really a good sport… A third reason might be that late in life, in the mids, I belatedly learned to fly and gained my glider pilot's license now expired on several Bergfalke types, one of them red, much like in the photo. Not the most elegant, and certainly not the most quiet of gliders I flew, but a true classic. I feeling a twinge of guilt talking about gliders other than card models.
Now I feel better. I have this habit of making vitual models out of card models. Leif, I very much enjoyed the video of the RC Nemere. John, after your Coca-Cola-bottle-cap-sized Colditz escape glider, you may now feel absolutely free to talk your heart out about non-paper gliders.
I've already done so for quite a while :. Most uncomfortable! It could also be used a single-seat trainer. The photo shows Roman's testbuild during the design process, hence some remaining imperfections. I'm looking forward to this one! It would be interesting to learn how Roman managed to make the canopy so nicely rounded. Roman has promised me to get back shortly about availability, etc. Waiting for more on the Bergfalke and the other models by Roman Seissler, I'll return to Hungary for a bit longer.
I arrived there in the search for ever more material on the Nemere, and this is where I really struck gold. The link goes to a search result arrived at by Google of Hungarian electronic books.
See pp,. If you then browse the rest of the pdf-file of this book, you'll find the same quality material for sailplane after sailplane, glider after glider. This is the absolutely most generous gift I've come across on the internet that I can remember right now.
And the very best thing about it is that it is not a scan - I believe it is a pdf-file of the printer's original, which means that both illustrations and text are absolutely clean and undistorted. Examples in just a little bit. All the extra material in form of photos and text you can wish for - and in perfectly good English right from the start! Like the similar site for Polish sailplanes encountered earlier in this thread, this is a goldmine for historical material.
A lot of advanced glider theory, but also see-through images of several gliders. In particular, one page about the Nemere p. Otherwise I have not saved this book, since - like the first one - it is in Hungarian and mostly theoretical.
As it turns out, I believe the work collected here is the original source for all drawings available on the internet of the Nemere, to give just one example.
And I'll add to that bulk of work here, republishing all the major drawings I have found of the Nemere in these two books. In the illustrations to follow, I have run explanatory captions through an online translater and copied the result into the pages published here for high-quality drawings, download the original books - even single pages from the books are just a bit too large to publish here.
The rest of the drawings here are from the first book, Hungarian Sailplanes. The first interesting features of this drawing is the diagram at top left, which is a calculation of time spent by Lajos Rotter during his flight spiralling in thermals to gain height, in relation to time spent on course Berlin-Kiel. The quota is exceedingly low for his time - such a low value would not be achieved again until the end of the s, if I have understood it correctly.
The second most interesting feature from a modeling point of view is the drawing of the instrument panel, with legends detailing what kind of instruments were on board. I have incorporated a translation in the drawing. The philosophy was that the canopy should be jettisonable in an emergency, including the bulky instrument panel, to leave the pilot space to get out with his parachute on.
This meant that the external venturi and pitot tubes had to be mounted to the canopy, not the fuselage. No additions necessary. It includes fuselage sections in larger scale. It is a very detailed drawing of the cockpit, with levers and all. Studying it closely one can learn a lot about Rotter's design philosophy for the Nemere. Translations for the Hungarian legends around the fuselage, as well as the numbered legends, have been included in the drawing as republished here. The barograf was suspended in springs behind the pilots head.
There was also a crank for offsetting both ailerons up or down simultaneously, to effect profiles suitable for penetrating sink or headwind areas between thermals, or thermal spiralling. This was a most advanced feature for its day. The grey area is ply covered, and the rest is fabric over ribs.
With this, I'll leave the Hungarian gliding scene for now. Jan, you absolutely swamp me - I had no idea there were that many out-of-print books and other resources out there. Thank you! And I can't even blame my not-so-good French for not finding it, since your Swiss source has an option for viewing it in English! Expands into datasheets for the gliders they have designed. There is also a list of books still in print, which expands into sources for these books.
In fact, all three branches of this database have search options. I couldn't think of a single one, but the Swiss database could. And there was also an all-Swedish glider from ! It appears the company made most of the license-built German gliders subsidized by the Swedish Air Force to increasing the interest in flying during the war years and immediately after.
The Fi-1, although fully aerobatic, turned out to be too heavy, yet it did well at Orebro in the hands of a Danish pilot. And fully aerobatic, to boot. Both do exist as a papermodels: Combining the fuselage and canopy of the Gil, plus the wings of the Lis, plus a little tweaking here and there, might just do the job. What an attractive idea - the one an only Swedish vintage sailplane I'm aware of to date. And the colour scheme, according to the Swedish drawing archived at the j2mc Planeurs site was my favourite - cream wings and tails, with crimson fuselage pod.
One could always dream Studying details of the various vintage gliders that have been up for discussion here, and comparing them to Hans Jacob's book, I can very well believe that this must have been a kind of sailplane designer's bible at the time! The book is full of detailed sketches and photos of wood-and-fabric building practices, which I love.
Thank you, indeed, Jan! Next time: Two more vintage glider eBook library sources, to make the list complete. Rich - thanks for the reminder. BUT - we should take care to search for the right Wampir. Nice photo, and a drawing. Plus, most importantly, links to other sources: The Polish sailplanes site we've visited before. Leif, I have been following this thread about gliders and I am getting real tired of reinserting my jaw back in my head.
This is an outstanding find. Most of which above and beyond me but still very enjoyable. From the very first post this has taken me and us on a journey through history and flight. This glider is now on my must do list. Not that I will be able to fly her but has a place on my ceiling. I can't thank you and all the others who have added to this. I just don't have the words. Wad Cutter. Hello Waddie - can I add, to the superior Swiss source from Jan described in the post before the last, the two other souces for eBooks about sailplanes that I promised, just to keep them together?
Clicking on it downloads the scanned book as a pdf-file. Note that there are four bookcases in all, not just the first one you see. How's this one for solving the problem of confirming that a pre-selected turning point really has been achieved: … My wife and I solved this problem in the following way. An aerodrome is selected for the turning-point, and from my estimated average speed I calculate how many hours it will take me to reach it after 'getting away'.
When she sees me achieve this she waits for the agreed lapse of time, and then telephones the control officer at the aerodrome selected. She then tells him, in effect, 'Please go to the window, and overhead you will see a sailplane circling. Please then fire a green Very light at it and come back and confirm that I am right. In the latter case, she rings off, but phones again half an hour later with the same request.
If the sailplane fails to reach the turning-point, one ends up with one more disillusioned control-tower officer. If it does, it has to circle round the aerodrome until the next half-hour strikes, when, on seeing the green light, the pilot knows he has been marked, and turns for home. This was obviously before the age of onboard cameras and radios!
A classic book, translated into English. Includes chapters by several other authors. As with the Hungarian book I liked so much, this is an incredibly generous gift. A talented paper-model designer could spend the rest of his or her life making Slingsby gliders out of this book. How about the Slingsby Petrel p. Time now to explore… Leif PS. At both these sites there are collections of film clips, both period clips of vintage gliders, and modern clips of flying restored vintage gliders.
Beautiful - but I leave them for you to explore on your own. Leif, your last post with all the great links, provided us with a wealth of information. I have downloaded many books and will be reading for many weeks. The videos were a big surprise not knowing that any of these existed.
These will be viewed many more times. Thank you so much for sharing. The down side is, it's cutting into my building and Sim flying time. I agree with John. Right at the start of my summer holidays this will give me plenty of stuff to read. As a little aside: I like the combination of vintage sailplanes and glider tugs of the same vintage. Look at all the other models from that site too, there are some real gems amongst them! I don't know how to thank for this treasure chest of videos and books Leif.
Now to find the time and explore it to it's fullest. The soaring of this beautiful glider with the music in the back ground is better then the best it could be. It took me away. I have too much to learn about card stock modeling and gliders plus now I have to learn about Radio Control. I hope I have the funds and help to get into this. I have a glider a friend gave me but it only had rudder and elevator control and nothing else.
So it might be better to look around to find a model with everything else that this glider is missing. But free is still free. If I can ever find it I will post a photo. Thank you Leif. Martin - what a good idea to use Philippe Rennesson's models as tug aircraft for vintage gliders. Waddie - thanks for the Minimoa video; that was really something! Blushingly, not really having watched them, I must admit I did not appreciate that Chris Williams' videos were of models.
They are very beautiful indeed. I believe I'm now close to my saturation point in this search for sources of material relevant to sailplane paper modeling. Getting back to really existing paper models of sailplanes, this final installment for a while is about two useful resources for spiffying up instrument panels in existing kits. But there is also quite a lot of documentary material for each glider - plus a very useful resource for paper modelers, namely high-quality images of sailplane instruments and instrument panels, both vintage and modern.
Just to see how one could use a resource like this, I made new instrument panels for the Orlik sailplane, which just arrived in my mailbox.
Top right are the parts from the GPM Orlik kit. Note how the model have the instruments correctly divided between the nose former and a separate panel closer to the pilot,but incorrectly placed in some cases.
Further, the built-up, closed-in panel does not seem to conform to the sketch in the drawing, which I trust. At the bottom right is my attempt to place the instruments according to the sketch. I opted for a bare panel, simulating a simple bent metal sheet, with the instruments sticking out on the back side.
That is also more interesting to model. Compass centred, on top. What you see is left a photo of the instrument panel of the Sroka. Note that the placement of most instruments is fairly accurate, but the instruments themselves are figments of the author's imagination. For one thing, I do not believe that a s trainer glider in Poland was equipped with an artificial horizon.
So, bottom right, is my rendering of a Sroka panel. I replaced the artificial horizon with a largeish compass, which I think is what we see in the photo. The Sroka, like many sailplanes of its era, did have a gyro turn indicator. It could thus be flown blind in clouds if you had the experience and competence, although that is quite hard.
An artificial horizon certainly would have been a dream for pilots of the period, but I don't think they had them. The instrument at far left of the panel I'm not quite sure about, but I have adde a "nose up-down" indicator, which just might be possible.
Although not strictly necessary at all to fly a glider blind watching your airspeed works just as well, and is more important , such an instrument seem to have been common in gliders of the s to early s era.
My guess for the vertical instrument at the far right, culled from the original photo, is an oldfashioned type of variometer, looking much like a thermometer. This is like the Orlik above. The separate compass section at bottom will be backed up with further layers to get to the proper thickness shown iby the photo. Finally a red T-shaped release handle will be made from wire. It is a pity for such good originals. It's nice to know they're there, though.
Programs used were Photoshop for isolating the single instruments, and for culling small parts from the photo and straighten them up. Final assembly and panel backgrounds were made in Illustrator, importing the photoshopped instruments.
The whole job could be done just as well in e. Azjatycki Cukier. Czworgiem Oczu. Figlarne czytanie. Czytanie przy kominku i nie tylko. Zakochana w czytaniu Tudor 1 rok temu.
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I wracam! Winter is coming Tym razem w komiksie. Siostry w bibliotece. Majowo w ogrodzie Taka sytuacja Recenzja pisana emocjami. Kronika Zapowiadanych Lektur. Galewska-Kustra 3 lata temu. Pierogi pruskie. Mechaniczna Kulturacja. Krzysztof Ziemiec. Re-book blog. Epic Books. Thus, despite being expressly aware of the anchoring effect, participants were still unable to avoid it. According to this theory, once an anchor is set, people adjust away from it to get to their final answer; however, they adjust insufficiently, resulting in their final guess being closer to the anchor than it would be otherwise.
To use an earlier example, since Mahatma Gandhi obviously did not die at age 9, then people will adjust from there. If a reasonable number were given, though, there would be no adjustment. Therefore, this theory cannot, according to its critics, explain the anchoring effect. According to Tversky and Kahneman's theory, this is impossible, since anchoring is only the result of conscious adjustment. In short, selective accessibility proposes that when given an anchor, a judge i.
Assuming it is not, the judge moves on to another guess, but not before accessing all the relevant attributes of the anchor itself. Then, when evaluating the new answer, the judge looks for ways in which it is similar to the anchor, resulting in the anchoring effect. According to this theory, providing an anchor changes someone's attitudes to be more favorable to the particular attributes of that anchor, biasing future answers to have similar characteristics as the anchor.
Leading proponents of this theory consider it to be an alternate explanation in line with prior research on anchoring-and-adjusting and selective accessibility. However, more recent studies have shown the opposite effect: sad people are more likely to use anchoring than people with happy or neutral mood.
In a study concerning the effects of anchoring on judicial decisions, researchers found that even experienced legal professionals were affected by anchoring.
This remained true even when the anchors provided were arbitrary and unrelated to the case in question. People high in agreeableness and conscientiousness are more likely to be affected by anchoring, while those high in extraversion are less likely to be affected. A recent study on willingness to pay for consumer goods found that anchoring decreased in those with greater cognitive ability, though it did not disappear.
The anchoring effect is where we set our estimation for the true value of the item at hand. In this way, a deliberate starting point can strongly affect the range of possible counteroffers. However, multiple studies have shown that initial offers have a stronger influence on the outcome of negotiations than subsequent counteroffers.
During the workshop, a group of participants is divided into two sections: buyers and sellers. Each side receives identical information about the other party before going into a one-on-one negotiation. Following this exercise, both sides debrief about their experiences. The results show that where the participants anchor the negotiation had a significant effect on their success. Northcraft and Neale conducted a study to measure the difference in the estimated value of a house between students and real-estate agents.
In this experiment, both groups were shown a house and then given different listing prices. After making their offer, each group was then asked to discuss what factors influenced their decisions. In the follow-up interviews, the real-estate agents denied being influenced by the initial price, but the results showed that both groups were equally influenced by that anchor.
Janiszewski and Uy investigated the effects of precision of an anchor. Participants read an initial price for a beach house, then gave the price they thought it was worth. They received either a general, seemingly nonspecific anchor e.
The authors propose that this effect comes from difference in scale; in other words, the anchor affects not only the starting value, but also the starting scale. A Psychological Interpretation of Drawings and Paintings. Alexandra Publishing. ISBN Retrieved 27 August Alan; Kahneman, Daniel Psychological Science. Stone A focusing illusion' PDF. CiteSeerX PMID Retrieved 29 May Journal of Personality and Social Psychology.
Journal of Experimental Psychology: General. The Journal of Socio-Economics. Journal of Behavioral Decision Making. Journal of Risk and Uncertainty. Journal of Experimental Social Psychology. Archived from the original PDF on Retrieved Organizational Behavior and Human Decision Processes. Blair G. Judgment and Decision Making. Personality and Social Psychology Bulletin.
International Journal of Forecasting. Economics Letters. Ohio St. Kaplan Publishing. Further reading[edit]Serfas, S. Gabler research. Gabler Verlag. Retrieved April 9, By using this site, you agree to the Terms of Use and Privacy Policy. Please help improve this article by adding citations to reliable sources. Unsourced material may be challenged and removed. A basic ER model is composed of entity types which classify the things of interest and specifies relationships that can exist between entities instances of those entity types.
In software engineering, an ER model is commonly formed to represent things a business needs to remember in order to perform business processes.
Consequently, the ER model becomes an abstract data model, that defines a data or information structure which can be implemented in a database, typically a relational database. Entity—relationship modeling was developed for database design by Peter Chen and published in a paper. Contents1 Introduction2 Entity—relationship model2. It does not define the business processes; it only presents a business data schema in graphical form.
It is usually drawn in a graphical form as boxes entities that are connected by lines relationships which express the associations and dependencies between entities. An ER model can also be expressed in a verbal form, for example: one building may be divided into zero or more apartments, but one apartment can only be located in one building. Entities may be characterized not only by relationships, but also by additional properties attributes , which include identifiers called 'primary keys'.
Diagrams created to represent attributes as well as entities and relationships may be called entity-attribute-relationship diagrams, rather than entity—relationship models.
An ER model is typically implemented as a database. In a simple relational database implementation, each row of a table represents one instance of an entity type, and each field in a table represents an attribute type. Note that the conceptual-logical-physical hierarchy below is used in other kinds of specification, and is different from the three schema approach to software engineering.
Conceptual data modelThis is the highest level ER model in that it contains the least granular detail but establishes the overall scope of what is to be included within the model set.
The conceptual ER model normally defines master reference data entities that are commonly used by the organization. Developing an enterprise-wide conceptual ER model is useful to support documenting the data architecture for an organization.
A conceptual ER model may be used as the foundation for one or more logical data models see below. The purpose of the conceptual ER model is then to establish structural metadata commonality for the master data entities between the set of logical ER models.
The conceptual data model may be used to form commonality relationships between ER models as a basis for data model integration. Logical data modelA logical ER model does not require a conceptual ER model, especially if the scope of the logical ER model includes only the development of a distinct information system. The logical ER model contains more detail than the conceptual ER model.
In addition to master data entities, operational and transactional data entities are now defined. The details of each data entity are developed and the relationships between these data entities are established. The logical ER model is however developed independently of the specific database management system into which it can be implemented.
The physical ER model is normally developed to be instantiated as a database. Therefore, each physical ER model must contain enough detail to produce a database and each physical ER model is technology dependent since each database management system is somewhat different.
The physical model is normally instantiated in the structural metadata of a database management system as relational database objects such as database tables, database indexes such as unique key indexes, and database constraints such as a foreign key constraint or a commonality constraint.
The ER model is also normally used to design modifications to the relational database objects and to maintain the structural metadata of the database. The first stage of information system design uses these models during the requirements analysis to describe information needs or the type of information that is to be stored in a database.
The data modeling technique can be used to describe any ontology i. In the case of the design of an information system that is based on a database, the conceptual data model is, at a later stage usually called logical design , mapped to a logical data model, such as the relational model; this in turn is mapped to a physical model during physical design. Note that sometimes, both of these phases are referred to as 'physical design.
An entity is an abstraction from the complexities of a domain. When we speak of an entity, we normally speak of some aspect of the real world that can be distinguished from other aspects of the real world. An entity may be a physical object such as a house or a car they exist physically , an event such as a house sale or a car service, or a concept such as a customer transaction or order they exist logically—as a concept.
Although the term entity is the one most commonly used, following Chen we should really distinguish between an entity and an entity-type. An entity-type is a category. An entity, strictly speaking, is an instance of a given entity-type. There are usually many instances of an entity-type. Because the term entity-type is somewhat cumbersome, most people tend to use the term entity as a synonym for this termEntities can be thought of as nouns.
Examples: a computer, an employee, a song, a mathematical theorem, etc. A relationship captures how entities are related to one another. Relationships can be thought of as verbs, linking two or more nouns. Examples: an owns relationship between a company and a computer, a supervises relationship between an employee and a department, a performs relationship between an artist and a song, a proves relationship between a mathematician and a conjecture, etc.
The model's linguistic aspect described above is utilized in the declarative database query language ERROL, which mimics natural language constructs. ERROL's semantics and implementation are based on reshaped relational algebra RRA , a relational algebra that is adapted to the entity—relationship model and captures its linguistic aspect.
Entities and relationships can both have attributes. Examples: an employee entity might have a Social Security Number SSN attribute, while a proved relationship may have a date attribute.
Every entity unless it is a weak entity must have a minimal set of uniquely identifying attributes, which is called the entity's primary key. Entity—relationship diagrams don't show single entities or single instances of relations. Rather, they show entity sets all entities of the same entity type and relationship sets all relationships of the same relationship type.
Examples: a particular song is an entity; the collection of all songs in a database is an entity set; the eaten relationship between a child and her lunch is a single relationship; the set of all such child-lunch relationships in a database is a relationship set. In other words, a relationship set corresponds to a relation in mathematics, while a relationship corresponds to a member of the relation.
Certain cardinality constraints on relationship sets may be indicated as well. Mapping natural language[edit]Chen proposed the following 'rules of thumb' for mapping natural language descriptions into ER diagrams: 'English, Chinese and ER diagrams' by Peter Chen. Relationships, roles and cardinalities[edit]In Chen's original paper he gives an example of a relationship and its roles. He describes a relationship 'marriage' and its two roles 'husband' and 'wife'.
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