[Clover] Eco Analysis by 辰

bzr2915UID: 2612029

看了 很有收获 收藏~

missingusaUID: 2625832

The financial crisis examined
Heroes and villains(坏人, 恶根)

BOOKS on the credit crunch(紧要关头; 困境; 转折点) seem to be multiplying more quickly than subprime(次级) mortgages(抵押) during the housing(供给住宅, 住宅群, 住房供给) bubble. At least these efforts, both by journalists on the Wall Street Journal, approach the crisis from different angles. Gregory Zuckerman looks at those investors who tried to bet on the bubble’s demise(不动产的)转让; 遗赠) whereas Scott Patterson looks at the funds that used computer-driven models to try to beat the markets.

Mr Zuckerman tells the more compelling of the two stories. His hero is John Paulson, a hedge-fund manager who was hardly known in 2005, having done little more than carve out(雕刻,开拓,创业) a moderately successful record in the market niche(小生境) of merger arbitrage(仲裁, 套汇, 套利交易). On the advice of a colleague named Paolo Pellegrini, Mr Paulson started to bet against the housing bubble.

He was early, but not too early; other investors had made the bet before him and been flummoxed(使惶惑, 打乱, 使狼狈, 使混乱) when house prices rose even further. In addition, the newfangled(新奇的, 新制的) structured products created by the likes of Bear Stearns and Citigroup gave Mr Paulson a method of betting on falling house prices that had not previously been available. Even so, his investors were sceptical(怀疑论的, 怀疑的), fearing that Mr Paulson was straying(迷路, 偏离, 漂泊, 漂泊游荡) from his core area of expertise. The hedge-fund manager’s initial attempt to raise money attracted just $147m—mere loose(释放) change by the standards of his corner of the industry.

The trade looked unattractive to many professionals. It required Mr Paulson to buy a form of insurance against the possibility that mortgage(抵押)-backed securities would default(疏怠职责, 缺席, 拖欠, 默认). If he was wrong, the insurance would prove worthless. Insiders took the complacent(自满的, 得意的) view that American house prices could never fall at the national level, and that Mr Paulson was making a dumb(无说话能力的, 不说话的, 无声音的) bet. “Our models are fine,” said a Bear Stearns expert in July 2006. “We’ve been doing this for 20 years.” His firm would last barely(仅仅, 刚刚, 几乎不能) another 20 months.

But the corollary(必然的结果, 系, 推论) of this scepticism(怀疑论, 怀疑主义) was that the insurance was very cheap. When Mr Paulson was proved right in 2007 and the insurers(保险业者, 保险公司) paid out, his credit funds made an average return of 440%. Mrs Pellegrini was unaware of her husband’s share of this gain until she checked her bank balance on an ATM; $45m had been deposited(存放, 堆积) into their joint account(两人共有之银行帐户).

If Mr Paulson’s coup(砰然而有效的一击, 妙计, 出乎意料的行动, 政变) was down to a (well-reasoned) hunch(肉峰, 预感, 大块), the careers of the investors featured in Mr Patterson’s book are based on rigorous(严格的, 严酷的, 严峻的) mathematics, or at least that is what they believe. Investing, once a liberal(慷慨的, 不拘泥的, 宽大的, 自由主义的) art, has been taken over by the “quants”(量子, 量子论), a shorthand term for those who use quantitative models to exploit anomalies(变态,反常,畸形物) in the market. Some of these men were indeed( (加强语气)确实) brilliant; Jim Simons of Renaissance Technologies won the Veblen medal, a leading mathematics prize.

The problem with the models was that they gave investors certainty when none should have existed. All too often(时常), as Nassim Taleb, author of “The Black Swan”, has pointed out, the models failed to take account of the extremes, when prices moved faster than predicted. And the actions of the quants themselves, by buying and selling certain types of assets, altered the behaviour of the market.

Mr Patterson’s book serves as a quick sketch(略图, 草图, 概略) of some of the leading players in the industry. But it falls short(达不到) on two counts(项). First, the author clearly feels the subject is too dry for the general reader so overcompensates(对...给予过多的补偿) with purple prose(散文). “Beneath the calm surface,” he writes, “a cataclysm(政治或社会上的任何巨变) was building like magma((有机物或矿物的)稀糊, 岩浆) bubbling(起泡, 潺潺的流) to the surface of a volcano.” Even a maths whizz((使)飕飕作声, 呼啸) could lose count of the clichés(陈词滥调) here.

Second, the use of mathematical models may have actually lured(引诱) banks into danger, though the author does little to explain that. Many of his main characters are hedge-fund managers who appear to have been chosen more for their love of poker (a recurring(复发, 重现, 再来) theme) than for their importance. Their actions made the market wobble(摇晃, 摇摆, 游移不定) in August 2007, but they were not at the heart of the subprime crisis and they are barely(仅仅, 刚刚, 几乎不能) mentioned in Mr Zuckerman’s account. This narrative does not live up to(实践, 做到) Mr Patterson’s apocalyptic(启示录的, 天启的) subtitle.

summary: housing bubble
             approach the crisis from different angles
             beat the markets
             on the advice of sb.
             core area of expertise
             take the complacent view (+that....):google不到的一个i用法
             be deposited into their joint account
             exploit anomalies in the market: exploit international market         
             all too often: 通常
             faster than predicted
             altere the behaviour of the market
             serve as a quick sketch of: 对....的一个概览
             falls short on two counts: 达不到两项
             like magma bubbling to the surface of a volcano
             lure .... into (danger)            
             do little to explain that
             make the market wobble

missingusaUID: 2625832

The Difference Engine: Hold the phone

IN THE days when you could buy germanium(锗) diodes(二极管), variable capacitors(电容器) and earphones from war-surplus(过剩的, 剩余的) stores for pennies, your correspondent(通讯记者, 通信者)—like many of his schoolboy contemporaries(当代的, 同时代的)—built a solid-state(使用电晶体的, 不用真空管的) version of his grandparents’ crystal-set to pull in short-wave radio broadcasts from around the world. Though such sets were used only for receiving, and therefore didn’t need a carefully designed resonating((使)共鸣, (使)共振) antenna like a transmitter, the biggest problem with them always was constructing an effective enough dipole([物]双极子, 偶极) aerial(天线).

This usually comprised(包含, 由...组成) a length of 18-gauge(标准尺) insulated(绝缘的) copper-clad(在金属外覆以另一种金属) steel wire strung loosely between a pair of tall trees, though quite the best antenna your correspondent ever devised relied on a couple of miles of barbed(有刺的, 具侧刺毛的)-wire surrounding a neighbour’s pasture(牧地, 草原, 牧场). Whatever the solution, the lesson most teenage radio-builders learned was that no matter how much time you spent getting the receiver to work efficiently, you would always devote three times more to fiddling(要求高精度的，需要手巧的) with the aerial(天线).

That still seems to be the case. Though there are a number of software tools available these days to help calculate an aerial’s parameters, antenna design is nothing short of a black art practised by an engineering priesthood(教士, 僧侣, 神父). None more so than designing antennas for mobile phones. All the fuss(忙乱) over Apple’s latest piece of wizardry(巫术)—the incredibly elegant iPhone 4—losing signal strength and dropping calls when clasped in a certain manner shows how tricky placating the aerial gods remains.

The only mistake Apple made was to wrap the iPhone 4’s two main antennas—a shorter one for the phone’s Bluetooth, Wi-Fi and GPS radios, and a longer one for its voice and data transceivers(无线电收发机, 收发器)—around the outer perimeter of the device, rather than embed(使插入, 使嵌入) them around the inside of the case. Presumably(推测起来, 大概), this was done to save space: the iPhone 4 is narrower and even more densely packed than its predecessor, the iPhone 3GS.

The consequence of using external antennas was predictable(可预言的) and (despite what Apple has insisted but is perhaps now ready to admit) has nothing whatsoever(无论什么) to do with a faulty formula used for calculating the number of bars that indicate signal strength. So, don’t expect any downloadable revision of the bar-strength formula to magically solve the issue of dropped calls.

But before addressing the drawbacks(缺点, 障碍) of exposed antennas, a word or two about signal strength. First, those one-to-five bars found at the top of mobile-phone displays indicating the strength of the wireless signal locally are just that—an indicator like a warning light rather than a gauge showing an actual value. If a one-bar signal allows you to make an uninterrupted call, then it is every bit as good as a five-bar signal. As such, then, a five-bar scale is pretty meaningless. So, why bother with it? Good question.

Experts reckon the weakest signal (ie, one bar) that an iPhone using the latest upgrades to AT&T’s zippy(敏捷的, 活泼的) third-generation network can detect without dropping a call or data connection is -113dBm (dBm is a measure of power in decibels relative to one milliwatt(毫瓦), with anything less than 0dBm being a fraction of 1mW). At the other extreme, a signal strong enough never to drop a call (five bars) is set arbitrarily(武断地, 任意地, 专横地) at -100dBm. But that is far from the strongest signal around. Get close to a cellular(细胞的) tower with a microwave meter and you will see signal strengths in excess(过度地, 过分) of -60dBm.

What this means, of course, is that there is no difference—as far as an iPhone’s (or any other phone’s) five-bar meter is concerned—between the absolute maximum signal strength the device is ever likely to encounter and the signal selected as being strong enough to warrant(保证, 辩解, 担保) five bars. Both will indicate the same five-bar reading. Apple can therefore tinker(做焊锅匠, 笨拙的修补) to its heart’s content with the arbitrary upper limit, by allocating(分派, 分配) more or fewer dBm per bar. But there is nothing it can do with a software patch about the fixed lower limit, below which the phone cannot maintain a call. That is a function of the network, the antenna design and the sensitivity(敏感, 灵敏(度), 灵敏性) of the radio chip.

Why, then, does the new iPhone drop calls more than usual? Ah, those pesky(烦恼的, 麻烦的, 讨厌的) external antennas. Grip(紧握, 紧夹) them in a particular way, and a five-bar signal can fall to one or two bars—provided it were only just strong enough to trigger(引发, 引起, 触发) a five-bar rating in the first place. If the signal is only one or two bars strong to start with, gripping(紧握, 紧夹) the phone in a certain way can then make it drop the call altogether. The reason is because bridging one or both of the gaps that separate the two different antennas wrapped around the outside of the phone with the hand causes them to be electrically shorted.

This has two negative effects. It detunes(解谐, 失谐, 误调) both antennas, especially the bigger, more sensitive one used by the cellular radio—all the more so if contact is also made near its point of maximum impedance(阻抗, 全电阻) (ie, the peak voltage-to-current ratio for the frequency concerned) at the bottom left-hand corner of the device. To work effectively, antennas have to resonate((使)共鸣, (使)共振) at their operating frequency. Increasing their length and adding a dielectric(电介质, 绝缘体) like the human body to the circuit lowers the resonant frequency markedly(显著地, 明显地), making it difficult for the antenna to do its job.

At the same time, coupling an electrically conductive(传导的) lump(块) of flesh (the body is around 60% salty water) into the circuit attenuates(削弱) the signal, by diverting(转移, 转向, 使高兴) some of its radio-frequency energy to the user’s body where it is turned it into heat. Folks in the know reckon the body can siphon off(吮吸) as much as 20dBm in this way—enough to turn a marginal(记在页边的, 边缘的, 边际的) five-star rating into a dropped call.

What’s to be done about it? The simple answer is to buy a $30 rubber “bumper case” for the iPhone 4 and put up with the clumsy appearance and difficulty of plugging the device into various attachments. Doing so, however, will put a wide enough gap between the dielectric(非传导性的) hand and the antenna to minimise(将...减到最少) the detuning
(解谐, 失谐, 误调[谐]) effect. Sticking(粘的, 有粘性的) a thin strip(条, 带) of insulating(绝缘的) tape over the offending gaps (especially the one at the lower left-hand edge) is a waste of time. We are dealing here not with a simple DC circuit but with radio-frequency currents alternating at over a billion cycles a second, where a sliver of insulator acts merely as a large capacitor(电容器)—in other words, a short circuit.

So, until Apple redesigns the iPhone 4’s external antennas—putting them inside the case where they used to be and where they belong—users will have to learn to hold the blessed thing in an unholy manner. And as Apple rarely admits to technical blunders(大错, 失误), we will have to wait another year for it to quietly correct the antenna design with the release of the current model’s replacement. By then, of course, the iPhone will have plenty of competition that will have doubtless learned from Apple's mistake.