Effectiveness of a Direct Adaptive Control Algorithm

Effectiveness of a Direct Adaptive Control Algorithm In this research, the authors study the effectiveness of applying a direct adaptive control algorithm for both vibration suppression and damage detection. Combining vibration suppression and damage detection in civil engineering structures allows the implementation of a more effective control system since the model reference represents more accurately the real structure. The adaptive algorithm chosen in this study is the sliding mode and model reference control algorithm, with an online identification procedure based on tracking error. In order to test the effectiveness of the method, a numerical investigation is presented, performed to a MDOF shear building. The study successfully uses the adaptive control algorithm to damage detection and vibration suppression of the MDOF shear-type structure aforementioned. The study first presents the governing relations of a general structural system, such as the equations of motion and its state space representation. Then, it presents the control canonical forms and the transformations that are useful to the application of the model reference adaptive control. These canonical form allow the separation from assignable dynamics and internal dynamics that are not affected from control input, and are applicable to both SISO and MIMO cases. It shows that a correct selection of a reduced measure of the state variables can guarantee exact output reference tracking. After this, the control strategy via sliding mode control and model reference control are presented. The reference model is defined in a way that the system response approaches or tracks the desired reference response. The slide mode control objective is to make the output to track a desired behavior, which means that the output error zero. This goal is achieved by sliding along a line, defined b y a weighting parameter that defines the convergence rate. The control law is therefore defined in a way that the states in canonical form match the sliding line. In this study, the online identification procedure is based on the asymptotic convergence to zero of the tracking errors and the stability of the method is proved by showing asymptotic stability convergence based on Lyapunov function. The numerical investigation performed in a 3DOF shear type structure. The reference model and the actual model differ in damping ratio values. Not much detail is given regarding the tools used during the numerical investigation. In the numerical investigation it is evaluated the performance of collocated and noncollocated control cases. It is concluded that the model reference control is accurate in the output tracking and is successful in suppressing the excessive vibrations, and is effective in the identification of changes in the model, showing it can deal with changes in the plant due to damage. The numerical stability of the method is verified, and the on-line identification effectiveness is evaluated. It is concluded that large control efforts are required during abrupt changes in the plant parameters. The results are not compared to any other adaptive algorithm, so it is difficult to measure its effectiveness. The research is important in the sense that brings the concept of adaptive control by applying model reference adaptive algorithm with sliding mode control to civil engineering structures. It confirms the effectiveness of the method in tracking the system parameters, even after abrupt changes happen, and it is successful in controlling the response while remaining numerical stable. However, that are some weaknesses in this paper, such as: the loading type/duration/scheme applied to the structure is not presented. Therefore, the results of the research are difficult to be reproduced in order to expand the knowledge in the area. The results obtained by this algorithm implementation are not compared to others non-adaptive and adaptive methods. Consequently, it is difficult to assess the extent of the effectiveness of the method. The model reference adaptive control and the sliding mode control theoretical aspect is somehow confusing and lacking completeness, with too many direct citatio ns that introduce a fragmentation in the text.

Ecn 204 Final Exam Notes

Macro Final Exam Chapter 10: The Money Systems What assets are considered â€Å"Money†? What are the functions of money and the types of money? * W/o money, trade would require barter > Exchanging one good/service for another * unlikely occurrence that two people e/ have a good that other wants * 3 functions * Medium of exchange: an item buyers give to sellers when they want to purchase g/s * Unit of account: the yardstick ppl use to post prices & record debts * Store of value: an item ppl can use to transfer purchasing power from the present to the future * 2 kinds Commodity money: commodity with intrinsic value, i. e. gold coins * Fiat money: money w/o intrinsic value, used as money b/c of gov’t decree, i. e. dollar bills * Money in Can’n economy * Money supply (Money stock): the quantity of money available in the economy * Two assets should be considers: * Currency: the paper bills & coins in the hands of the general public * Demand deposits: balances in bank accounts that despositors can access on demand by writing a cheque/using debit card * Money Supply = currency + depositsWhat is the bank of Canada and its role? How do Banks create money? * Central Bank: an institution designed to regulate the money supply in the economy * Bank of Canada: the central bank of Canada * Established in 1935, nationalized in 1938, owned by Can’n gov’t * Managed by board of directors appointed by minister of Finance, composed of: governor, the senior deputy governor (7 yr terms), 12 directors (3 yr terms) * Four primary functions: * Issue currency, act as banker to commercial banks & Can’n gov’t, control money supply * Commercial Banks and Money Supply Although Bank of Canada alone is responsible for Canadian monetary policy, the central bank can control the supply of money only through its influence on the entire banking system * Commercial banks include credit unions, caisses populaires, and trust companies * Commercial banks can influence the quantity of demand deposits in economy and money supply * Reserves: cash that commercial banks hold * Fractional banking system > Keeps fraction of deposits as reserves, rest is loaned * Banks may hold more than this minimum amt if they choose * The reserve ratio, R Fraction of deposits that banks hold as reserves * Total reserves as % of total deposits * Bank T-account * T-account – simplified accounting statement that shows bank’s Assets & liabilities * Banks liabilities: deposits(what we put in the bank), Assets: Loans and reserves(What bank keeps) * R= Reserves/Deposits * Banks & money supply * $100 of currency is in circulation, determining impact on money supply: Calculate in 3 different cases * No banking system Public holds the $100 as currency; Money supply= $100 * 100% reserves banking system: banks hold 100% of deposits as reserves make no loans * MS = Currency (loans) + deposits = 0 +100 = 100 * Bank does not affect size of money supply * Fractional reserve banking system * R=10%: Reserves: 10, Loans: 90, Deposits: 100 * MS= $190 * When banks make loans > create money * Borrower gets: 90 in currency(asset), 90 in new debt/loan (liability) * Money Multiplier: The amt of money the banking system generates with each dollar of reserves * Money multiplier = 1/R R =10, 1/R = 10, 100 x 10 = 1000 * The Bank of Canada’s tools of Monetary Control * 1. Open-market operations * When it buys gov’t bonds from/ sells to the public * Foreign exchange market operations: when it buy/sells foreign currencies * MS increase when bank of Canada buys foreign currency with Canadian Currency; and decrease when BoC sells foreign currency * 2. Changing the overnight rate * Central banks act as bankers to commercial banks Bank rate : interest rate charged by bank of Canada on loans to the commercial banks * Since 1998 Bank of Canada as allowed commercial banks to borrow freely at the bank rate, paid commercial banks the bank rate , minus half percent, on their deposits at bank of Canada * Commercial banks never need to pay more than bank rate for short term loans, b/c they can always borrow from the Bank of Canada instead * Conversely, commercial banks never need to accept less than the bank rate, minus half a percent, when they make short-term loans, because they can always lend to the bank of Canada instead * Overnight rate: the interest rate on very short-term loans between commercial banks * Bank of Canada can alter the money supply by changing the bank rate, which in turn causes an equal change in overnight rate * A higher bank rate discourages commercial banks from borrowing from the Bank of Canada * A higher overnight rate discourages commercial banks from borrowing from other commercial banks * An increase in the overnight rate reduces the quantity of reserves in the banking system, which in turn reduces the money supply * Bank of Canada’s control of MS is not precise * Bank of Canada must wre stle w/ 2 problems that come from fractional-reserve banking * Does not control amt of money that: * Household choose to hold as deposits in banks * Commercial bankers choose to lend Chapter 11: Money Growth and Inflation How does the money supply affect the inflation & nominal interest rates? * Quantity theory of money: Price rises when gov’t prints too much money * Most economists believe the quantity theory is a good explanation of the long run behavior of inflation * Asserts that quantity of money determines value * 2 approaches: * Supply demand diagram MS determined by bank of Canada, banking system, consuers * In model, assume that BoC precisely controls MS & sets it at some fixed amt * MD (money demand) how much wealth ppl want to hold in liquid form * Depends on P: an increase in P reduces the value of money, so more money is required to buy goods & services * Thus: Quantity of money demanded is –vely related to the value of money +vely related to P, other thin gs equal (real income, interest rates, availability of ATMs) * * Results from Graph: Increasing MS causes P to rise * How does this work? Short version: * AT the initial P, an increase in MS causes excess supply of money * People get rid of their excess money by spending it on goods & services/ by loaning it to others who spent it * Result: increased demand of goods But supply of goods does not increase, so prices must rise * Other things happen in the short run, which we will study in later chapters) * Equation * Nominal Variables: are measured in monetary units * i. e. Nominal GDP, nominal interest rates (rate of return measured in $) nominal wage($ per/hour worked) * Real Variables: are measured in physical units * i. e. real GDP real interest rate (measured in output) real wage (measured in output) * Real vs. Nominal * Prices are normally measured in terms of money * Price of a compact disc: $15/cd * Price of a pepperoni pizza: $10/pizza A relative price: price of one good relat ive (divided by) another: * Relative price of CDs in terms of pizza: * Price of CD/Price of pizza = 15/10 = 1. 5 pizzas per cd * Relative prices are measured in physical units so they are real variables * Real vs. Nominal Wage * An important relative price is the real wage * W= nominal wage= price of labour $15/hr * P = price level = price of g&s $5/unit of output * Real wage is price of labour relative to price of output * W/P = 15/5 = 3 units output per hour * Classical theory of inflation: * Increase in overall level of prices * Over past 60 yrs, prices risen on avg of 4%/yr Deflation: people will wait for prices to drop on big ticketed items, dropped in the 20th century * In 1970s prices rose by 7%/yr * During 1990s, price rose at 2%/yr * Hyperinflation: extraordinary high rate * Quantity theory of money: explain long-run determinants of price lvl and inflation rate * Inflation is an economy-wide phenomenon that concerns the value of the economy’s medium of exchange * Whe n the overall price level rises, value of money falls * Inverse relationship b/w price & value of money * Value of money: * P = Price lvl (CPI/ GDP deflator) * P = price of basket of goods measured in money * 1/P is value of $1, measured in goods * Example: basket contains one candy bar, P = $2, Value of $1 is ? candy bar * The Classical Dichotomy Classical dichotomy: theoretical separation of nominal & real variables * Hume & the classical economists suggested that monetary developments affect nominal variables but not real variables * If the central bank doubles the MS, Hume & classical thinkers contend * All nom variables (including prices) will double * All real variables (Including relative prices) will remain unchanged * The neutrality of Money * Monetary neutrality: the proposition that changes in the MS do not affect real variables * Doubling money supply causes all nominal prices to double, what happens to relative prices? * Initially, relative price of cd in terms of pizza is * Price of cd/price of pizza = 15/10 = 1. pizzas per cd * After nominal prices double * 30/20 = 1. 5 pizza per cd * Relative price is unchanged * Monetary neutrality: proposition that changes in the MS do not affect real variables * Similarly, the real wage W/P remains unchanged, so†¦ * Quantity of labour supplied/demanded, total employment does not change * The same applies to employment of capital & other resources * Since employment of all resources in unchanged, total output is also unchanged by the MS * Most economists believe the classical dichotomy & neutrality of money describe the economy in the long run Does the money supply affect real variables like real GDP or the real interest rate? The velocity of Money: the rate at which money changes hands * Notation: * PxY = nominal GDP = price level x real GDP * M = money supply * V = velocity * Velocity formula: V = PXY/M * Pizza, Y = real GDP = 3000 pizzas, P= price of pizza = $10, P*Y = $30,0000, M = $10,000 * V=30,000 /10,000= 3, avg dollar was used in 3 transactions * Quantity Equation * M*V = P*Y * V = stable * So, a change in M causes nominal GDP (P*Y) to change by the same % * A change in M does not affect Y: money is neutral, Y is determined by tech & resources * So, P changes by the same % as P*Y and M * Rapid money supply growth causes rapid inflation How is inflation like a tax? Hyperinflation is generally defined as inflation exceeding 50%/month * Excessive growth in the MS always causes hyperinflation * Inflation tax: * When tax revenue is inadequate and ability to borrow is ltd, gov’t may print money to pay for its spending * Almost all hyperinflations start this way * The revenue from printing money is the inflation tax: printing money causes inflation, which is like a tax on everyone who holds money * The Fischer Effect * Rearrange definition of real interest rate: * Nominal interest rate = Inflation rate + real interest rate * Real interest rate is determined by saving & inve stment in the loanable funds market * MS growth determines inflation rate This equation shows how the nominal interest rate is determined * In long run, money is neutral, so a change in the money growth rate affects the inflation rate but not the real interest rate * So, nominal interest rate adjusts one-for-one with changes in the inflation rate * The inflation tax applies to people’s holdings of money, not their holdings of wreath * Fishcher effect: an increase in inflation causes an equal increase in the nominal interest rate, so the real interest rate is unchanged What are the costs of inflation? How serious are they? * The inflation fallacy: most ppl think inflation erodes real income * Inflation is a general increase in price of the things ppl buy & the things they sell (i. e. labour) * In long run, real incomes are determined by real variables, not inflation rate * Shoeleather costs: the resources wasted when inflation encourages ppl to reduce their money holdings * In cludes the time & transactions costs of more frequent bank withdrawals * Menu costs: the costs of changing prices Printing new menus, mailing new catalogs * Misallocation of resources from relative-price variability: Firms don’t all raise prices @ the same time, so relative prices can vary which distorts the allocation of resources * Confusion & inconvenience: inflation changes the yardstick we use to measure transactions, complicates long-range planning & the comparison of dollar amts over time * Tax distortions: inflation makes nominal income grow faster than real income, taxes are based on nominal income, & some are not adjusted for inflation, so†¦ inflation causes ppl to pay more taxes even when their real incomes don’t increase * Arbitrary redistributions of wealth Higher-than-expected inflation transfers purchasing power from creditors to debtors: debtors get to repay their debt w/ dollars that aren’t worth as much * Lower-than-expected inflation tran sfers purchasing power from debtors to creditors * High inflation is more variable & less predictable than low inflation * So, these arbitrary redistributions are frequent when inflation is high * Costs are high for economies experiencing hyperinflation * For economies w/ low inflation ( 0, â€Å"Capital outflow†, domestic purchases of foreign assets exceed foreign purchases of domestic assets * Capital is flowing out of country * When NCO < 0, â€Å"Capital inflow†, foreign purchases of domestic assets exceed domestic purchases of foreign assets * Capital is flowing into the country * Variables that Influence NCO * Real interest rates paid on foreign assets or domestic assets * Perceived risks of holding foreign assets * Gov’t policies affecting foreign ownership of domestic assets * The equality of NX & NCO * An accounting identity: NCO = NX * Arises b/c every transactions that affects NX also affects NCO by the same amt (And vice versa) * When a foreigner pur chases a good from Canada, * Can’n exports & NX increase The foreigner pay w/ currency or assets, so the Can’n acquires some foreign assets, causing NCO to rise * An accounting identity: NCO=NX * Arises b/c every transaction that affects NX also affects NCO the same amt ( & vice versa) * When a Can’n citizen buys foreign goods, * Can’n imports rise, NX falls * The Can’n buyer pays w/ Can’n dollars or assets, so the other country acquires Can’n assets, causing Can’n NCO to fall * Saving, Investment, & international Flows of Goods & Assets * Y = C + I + G + NX accounting identity * Y – C – G = I + NX rearranging terms * S = I + NX since S = Y – C – G * S = I + NCO since NX = NCO * When S > I, the excess loanable funds flow abroad in the form of positive net capital outflow, NCO >0 * When S e =P*/P implies that the nom exchange rate between 2 countries should equal the ratio of price lvls * If the 2 cou ntries have diff inflation rates, then e will change over time: * If inflation is higher in Mexico than in Canada, Then P* rises faster than P, so e rises – the dollar appreciates against the peso * If inflation is higher in Canada than in Japan, then P rises faster than P*, so e falls- the dollar depreciates against the yen * Limitations of PPP theory, why exchange rates do not always adjust to equalize prices across countries: * Many goods cannot easily be traded: * i. e. haircuts, going to movies * Price differences on such goods cannot be arbitraged away * Foreign, domestic goods not perfect substitutes: * i. e. some Can’n consumers prefer Toyatos over Chevys * Price differences reflect taste differences * Nonetheless, PPP works well in many cases, especially as an explanation of long-run trends * i. e.PPP implies: the greater a country’s inflation rate, the faster its currency should depreciate (relative to a low-inflation country like Canada) * Interest ra te determination in a small open economy w/ perfect Capital mobility * Why do interest rates in Canada & the U. S. tend to move up & down together? * Canada is a small open economy w/ perfect capital mobility * â€Å"small† = small part of the world economy * Canada is an economy w/ perfect capital mobility b/c * Can’ns have full access to world financial markets, * And the rest of the world has full access to the Can’n fin’l market * This means that the real interest rate in Canada should equal the real rate prevailing in the world U. S. r= r^w * Perfect Capital mobility: theory that real interest rate in Canada should equal that in the rest of the world is known as interest rate parity * Limitations: real interest rate in Canada is not always = to the real interest rate in the rest of the world b/c†¦ * Fin’l assets carry w/ them the possibility of default * Fin’l assets offered for sale in different Chapter 13: Macroeconomic theory of the open economy In an open economy, what determines the real interest rate? The real exchange rate? * Market of loanable Funds S=I + NCO * Supply of loanable funds = saving * A dollar of saving can be used to finance * The purchase of domestic capital * The purchase of foreign asset * So, demand for loanable funds=I + NCO * S depends +vely on the real interest rate, r * I depends –vely on r * Real interest rate, is the real return on domestic assets * A fall in r makes domestic assets less attractive relative to foreign assets * Can’ns purchase more foreign assets * Can’ns purchase fewer domestic assets * NCO rises * The supply & demand for loanable funds depend on the real interest rate * A higher real interest rate encourages ppl to save & raises the quantity of loanable funds supplied * The interest rate adjusts to bring the supply & demand for loanable funds into balance * At eq’m interest rate, the amt that ppl want to save exactly balances the des ired quantities of domestic investment & foreign investment * Loanable funds market diagram * R adjusts to balance supply & demand in the LF market * Both I & NCO depend –vely on r, so the D curve is downward-sloping * * In small open economy w/ perfect capital mobility, i. e. Canada, the domestic interest rate = world interst rate * As a result, the quantity of loanable funds made available by the savings of Can’ns does not have to equal the quantity of loanable funds demanded for domestic investment * The difference between these two amts is NCO * * How are the markets for loanable funds & foreign-currency exchange connected? The market for foreign-currency exchange exists b/c ppl want to trade w/ ppl in other countries, but they want to be paid in their own currency * 2 side of foreign-currency exchange market are represented by NCO & NX * NCO represents the imbalance between the purchases & sales of capital assets * NX represents the imbalance b/w exports & imports of goods & services * Another identity from preceding chapter: NCO = NX * In the market for foreign-currency exchange, * NX is the demand for dollars: foreigners need dollars to buy Can’n NX * NCO is the supply of dollars: Can’n residents provide/give dollars when they buy foreign assets * S=I + NCO > S – I =NX * What price balances the supply & demand in the market for foreign-currency exchange? * The real exchange rate (E) = e*P/P* The Can’n exchange rate(E) measures the quantity of foreign g/s that trade for one unit of Can’n g/s * E is the real value of a dollar in the market for foreign-currency exchange * The demand curve for dollars (NX) is downward sloping b/c a higher exchange rate makes domestic goods more expensive * The supply curve (NCO) is vertical b/c the quantity of dollars supplied for NCO is unrelated to the real exchange rate * Increase in E makes Can’n goods more expensive to foreigners, reduces foreign demand for Canâ⠂¬â„¢n goods & dollars, does not affect NCO/supply of dollars * The real E adjusts to balance the S & D for dollars * At Eq’m E, the demand for dollars to buy NX exactly balances the supply of dollars to be exchanged into foreign currency to buy assets abroad * Disentangling S&D When can’n resident buys imported goods does the transaction affect s/d in foreign exchange market? * The demand for dollars decrease * The increase in imports reduce NX which we think of as demand for dollars (NX= net demand for dollars) * When foreigner buys Can’n asset, does the transaction affect supply/ demand in the foreign exchange market * The supply of dollars falls * NCO = Net supply of dollars How do gov’t budget deficits affect exchange rate & trade balance? * The effects of a budget deficit * National saving falls * The real interest rate rises * Domestic investment & net capital outflow both fall * The real exchange rate appreciates * Net export fall (or the trade de ficit increases) * Eq’m in the Open Economy NCO is the variable that links these two markets: S = I + NCO, NCO =NX * In the market for loanable funds, supply comes from national saving & demand comes from domestic investment & NCO * In the market for foreign-currency exchange, suplly comes from NCO & demand comes from BX * * * Eq’m in the open economy * Prices in the loanable funds market & the foreign-currency exchange market adjust simultaneously to balance supply & demand in these two markets * As they, they determine the macroeconomic variables of national saving, domestic investment, NCO, and NX How do other policies or events affect the interest rate, exchange rate, and trade balance? The magnitude & variation in important macroeconomic variables depend on the following: * Increase in world interest rates * Gov’t budget deficits & surpluses * Trade policies * Political & economic stability * Three steps in using the model to analyze these events * Determin e which of the s/d curves e/ event effects * Determine which way the curves shift * Examine how these shifts alter the economy’s equilibrium * * * Increase in world interest rates * Events outside Canada that cause world interest rates to change can have important effects on the Can’n economy * In a small open economy w/ perfect mobility, an increase in the world interest rate†¦ * Crowds out domestic investment, * Cause NCO to increase & * Causes the dollar to depreciate * The effects of an increase in the gov’t budget deficit * * Gov’t budget deficits & surpluses * b/c a gov’t budget deficit represents negative public saving, it reduces national saving, and therefore reduces†¦ * the supply of loanable funds * NCO * The supply of Can’n dollars in the market for foreign-currency exchange * Trade Policy: is a gov’t policy that directly influences the quantity of goods @ services that a country imports/exports * Tariff: a tax o n imported goods * Imported quota: a limit on quantity of a good produces abroad and sold domestically * Initial impact is on imports – which affects NX NX are the sources of demand for dollars in the foreign-currency exchange market * Imports are reduced at any exchange rate, & NX will rise * This increases the demand for dollars in the foreign currency exchange market * * * There is no change in the market for loanable funds, and therefore, no change in NCO * B/c foreigners need dollars to buy Can’n NX, there is an increased demand for dollars in the market for foreign-currency * This leads to an appreciation of the real exchange rate * Effect of an import quota * An appreciation of the dollar in the foreign exchange market discourages exports * This offsets the initial increase in NX due to import quota * Trade policies do not affect the trade balance Political Instability & Capital Flight * Capital flight * Is large & sudden reduction in demand for assets located i n a country * Has its largest impact on the country from which the capital is fleeing, but it also affects other countries * If investors become concerned about the safety of their investments, capital can quickly leave an economy * Interest rates increase & the domestic currency depreciates * When investors around the world observed political problems in Mexico in 1994, they sold some of their Mexican assets and used the proceeds to by assets of the other countries * This increased Mexican NCO An increased demand for loanable funds in the loanable funds market leads the interest rate to increase * This increased the supply of pesos in the foreign-currency exchange market * * Chapter 14: Aggregate Demand & Supply What are economic fluctuations? What are their characteristics? * Over LR, Real GDP grows about 2%/yr on avg * In SR, GDP fluctuates around its trend * Recessions: falling real incomes & rising unemployment * Depressions: severe recessions (very rare) * SR economic fluctuat ions are often called business cycles * 3 facts about economic fluctuations * Are irregular & unpredictable * Most macro’c quantities fluctuate together * As output falls, unemployment rises Use mode of AD & AS to study fluctuations * Short run, changes in nominal variables (Ms or P) can affect real variables (Y/U-rate) How does the model aggregate demand & supply explain economic fluctuations? * Aggregate-demand curve – shows the quantity of goods & services that households, firms, & the gov’t want to buy @ each price level * Aggregate-supply curve- shows the quantity of goods & services that firms choose to produce and sell at each price level * Why does the aggregate-demand curve slope downward? What shifts the AD curve? * AD curve shows quantity of g/s demanded in the economy at any given P * Y=C+I+G+NX * Assume G fixed by gov’t policy Increase in P reduces the quantity of g/s demanded b/c: * The wealth effect (c falls) * The dollars ppl hold buy fewe r g/s so real wealth is lower * Ppl feel poorer * i. e. a stock market boom makes households feel wealthier, C rises, the AD curve shifts right; preferences: consumption, saving tradeoff; tax hikes/cuts * Interest rate effect (I falls) * Buying g/s requires more dollars * To get these dollars, ppl borrow more * Drives up interest rates * i. e. firms buy new computers; expectations, optimism/pessimism; Interest rates, monetary policy; investment tax credit/other tax incentives * The exchange rate effect (NX falls) * Real exchange rate= exP/P* Increase real exchange rate, Can’n exchange rate appreciates * Can’n exports more expensive to ppl abroad, imports cheaper to Can’n residents * i. e. booms/recessions in countries that buy our exports (recession in the U. S. ); appreciation/depreciation resulting from int’l speculation in foreign exchange market * Changes in G * Federal spending i. e defense; provincial & municipal spending i. e roads, schools What is the slope of the aggregate-supply curve in the short run? Long run? What shifts AS curve? * AS curve shows the total quantity of g/s firms produce & sell at any given P * Upward-sloping in short run * Vertical in long run Natural rate of output (Yn) us the amt of output the economy produces when unemployment is at its natural rate * Yn is also called potential output/full-employment output * Yn determined by the economy’s labour (L) capital (K), and natural resources(N), and on the lvl of tech(A) * Changes in L/Natural rate unemployment: immigration, Baby-boomers retire, gov’t policies reduce natural u-rate * Changes in K/H: Investment in factories, more ppl get college degrees, factories destroyed by a hurricane * Changes in natural resources(N): discovery of new mineral deposits, reduction in supply of imported oil, changing weather patterns that affect agricultural production * Changes in tech (A): productivity improvements from technological progress * An increase in P does not affect any of these, it does not affect Yn (Classical dichotomy) * Any even that changes any of the determinants of Yn will shift LRAS * i. e. immigration increases L, causing Yn to rise * Over the LR, tech progress shifts LRAS to the right & growth in the MS shifts AD to the right * Ongoing inflation & growth in output * The SRAs curves is upward sloping: * Over the period of 1-2 yrs, an increase in P causes an increase in quantity of g/s supplied * If AS is vertical, fluctuations in AD do ot cause fluctuations in output/employment * If AS slopes up, then shifts in AD do affect output & employment * Three theories: * Sticky wage theory, Imperfection- nominal wages are sticky in the short run, they adjust sluggishly, due to labour contracts; firms & workers set the nominal wage in advance based on Pe, the price lvl expected to prevail * If P>Pe, revenue is higher, but labour cost is not. Productions is more profitable, so firms increase output & employment * Hence, hi gh P causes higher Y, so the SRAS curve slopes upward * Sticky price theory, Imperfection- many prices are sticky in the short run: due to menu costs, the costs of adjusting prices, i. e. ost of printing new menus, the time required to change price tags * Firms set sticky prices in advance based on Pe * Suppose the BoC increases the MS unexpectedly, in LR P will rise * In SR, firms w/o menu costs can raise their P immediately * Firms w/ menu costs wait to raise prices, meantime , their prices are relatively low, which increase demand for their products, so they increase output & employment * Hence, higher P is associated w/ higher Y, so the SRAS curve slopes upward * Misperceptions- imperfection: firms may confuse changes in P with changes in the relative price of the products they sell, if P rises above Pe- a firm sees its price rise before realizing all prices are rising. The firms may believe its relative price is rising & may increase output & employment, * An increase in P can cause an increase in Y, making the SRAS curve upward-sloping * What 3 theories have in common: Y deviates from Yn, when P deviates from Pe * Y(Output) = Yn + a(P-Pe) * Yn-Natural rate of output (LR) * a>0, measures how much Y responds to unexpected changes in P * P, actually price lvl; Pe, expected price lvl * SRAS & LRAS The imperfections in these theories are temp, over time†¦ * Sticky wages & prices become flexible * Misperceptions are corrected * In LR†¦ * Pe = P, Y=Yn, AS is vertical * Unemployment is at its natural rate * Why the SRAS curve might shift * Everything that shifts LRAS shifts SRAS too * Also, Pe shifts SRAS: * If Pe rises, workers & firms set higher wages * At e/ P production is less profitable, Y falls, SRAS shifts left * * Economic fluctuations * Caused by events that shift the AD/AS curves * 4 steps to analyzing economic fluctuations: * Determine whether the event shifts AD & AS * Determine whether curve shifts left/right Use AD-AS diagram to see how the shift changes Y & P in the short run * Use AD-AS diagram to see how economy moves from new SR eq’m to new LR eq’m * I. e. Stock market crash : C falls, so AD shifts left; SR eq’m at B, P & Y lower, unemp higher; Over time Pe fals, SRAS shifts right, until LR eq’m at C, Y and unemp back at initial lvls * * i. e. oil prices rises: increases costs, shifts SRAS Left, SR eq’m at point B, P higher, Y lower, unemp higher; from A to B, stagflation: a period of falling output & rising prices; if policymakers do nothing: low employment causes wages to fall SRAS shifts right until LR eq’m at A, or policymakers could use fiscal/ monetary policy to increase Ad & accommodate AS shift: Y back to Yn, but P permanently higher

Humanities are not useless Essay

Humanities are the subjects such as history, philosophy, and literature which are concerned with human ideas and behaviors. This is only a general idea. The deeper meaning of studying humanities is that it is an academic approach to understanding people better, a way to enable us to develop better not only through four years university life but also in one’s entire life. Some people may say that humanities are useless because people cannot make considerable money with them. However, that is not the truth. Once someone has realized the value of studying humanities, this will be beneficial for his or her life. I study humanities because I believe I will gain plenty of meanings of life through the learning process. Most people think that humanities are useless, my mother is one of those people. She is always asking me that why would you waste our money and your time on such useless stuff. However, my father does not think so, he believes that everything has its own value, even humanities. In this case, I strongly agree with my father. The reason why my mother thinks that humanities are useless is that people cannot make good money with them; the jobs related to humanities are not well-paid. Actually this is a generalization which people have commonly. Nevertheless, people who think so are wrong. The truth is opposite. According to the article â€Å"Liberal Arts and the Advantages of Being Useless†, the author explains that even people with Liberal Arts degree have pretty much the same chance as other majors to end up making good money. Although humanities are useless for maximal one’s salary immediately after graduation, and bring a slightly greater risk of unemployment immediately after graduation, there is good evidence that Liberal Arts majors tend to earn higher salaries by midcareer. Besides, life is short, and it should not be all about money. There are other intangible things to pursue. â€Å"There are lessons to be learned from the humanities that were not available anywhere else† said by Julia T. Cadenhead(2001). According to the Syllabus of ACMA01, courses in humanities explore such fundamental questions as how we use language, how our ideas and thoughts on the human experience are expressed and interpreted, how we determine value of meaning, how we define ideas such as †truth† â€Å"beauty†, and â€Å"arts†. They consider ideas about meaning of life, the reasons for our thoughts and actions, and the values and principles that inform our laws, norms and customs those written and unwritten. Unlike science, there are not standard answers to these questions. Furthermore, different people grew up in different environments, they have various cultures, backgrounds, and languages. Studying humanities make people think in different ways and experience a journey that they have never taken before. In addition, people who are studying humanities are becoming more comprehensive and compassionate about one’s self and one’s community. Different from other subjects such as medicine and law which make people useful for specific purposes, humanities make people better citizens. During the learning process, people gain self-improvements because studying humanities can make people think meaningful questions that somehow change people’s life in a good way. For example, many prisoners do not have religions before they go to prison, but some of these people are found through religions. When they are not only learning religions but studying humanities as a whole, they reflect what they have done. They can tell the rights from wrongs. They are becoming better. After they are released from prison, they behave well, they become useful citizens. This is beneficial for both society and individuals. Humanities are not useless. They can make you earn considerable money; they can make you gain self-improvements; they can make you question things that may change your life. Once someone has discovered the value of studying humanities, his or her life will change. Reference: Jones, Nichlaos. â€Å"Liberal Arts, and the Advantages of Being Useless. † Academia. edu. n. p. n. d. Web. 5 Sept. 2013.

The Constitutionality of Prayer in Public Schools Essay

Many people agree against prayer in public schools, while others think that people should be able to express their religion in their own ways. In public schools, they are not allowed to hold prayers at all during the school day due to the mixed religion students that are attending the school. Over the past few years, this has become an extremely controversial issue in our nation. Many people find it proper to pray in school but many people also agree that it is extremely wrong and that if there is going to be pray in school, every religion should be addressed. The government cannot make a law about having a certain religion banned or allowed in a school setting. Children are allowed to pray on their own time as long as it does not†¦show more content†¦One major reason why prayer is not allowed in public schools is because people may find it offensive to them if they do not belong to they religion that the prayer is being said in. This has been an ongoing argument for many d ecades and it has not come to a conclusion yet. Everyone has their own beliefs and usually they do not affect others unless they are directed towards someone of another religion. If prayer is going to be formally present in public schools, that school should say a prayer in every religion. They could do this by having someone of each religion in that school come up with a new prayer each day. Another thing they could do is have a special prayer for each religion present whether it’s a Catholic, Jewish, Islamic, or even Buddhist prayer. If you want your child to pray and learn a religion in school, send them to a private school that follows a certain religion and that have certain religious beliefs. A major reason why I’m against prayer in public schools is because the public school system is created for all students and is paid for by tax payers and fellow citizens. I think that the public schooling system should remain neutral on religions issues die to the diversity of our students, tax payers, and our fellow citizens. A public school is set up so that anyone on any religion or race can obtain an education. ThereShow MoreRelatedShould Prayer Be Allowed? School?1623 Words   |  7 Pagesis too powerful and those that would agree that prayer should be allowed in school. On the flip side to that those that feel the government does not have enough power and tend to disagree with pear being allowed in school. Based off articles researched and statistics gathered as well summarized it can be determined that those that are of the conservative and or republican party tend to feel that the government should not have a say in prayer in school. This may be because of religious preference orRead MoreEssay about The Constitutionality of Prayer846 Words   |  4 PagesThe question of the constitutionality of prayer in our public schools and public school system has been an ongoing controversy for the past three decades. There is only one way to end the co ntroversy, and it is pertinent to the well being of our youth and our nation. We must keep church and state forever separate. Any form of prayer in the public school system is an explicit violation of the first amendment, is coercive, and harmful to not only our nations children, but to the nation itself. TheRead MoreAlabama V. Jaffree ( 1985 )1737 Words   |  7 Pagessilence for meditation or voluntary prayer violate the First Amendment Establishment Clause that is applied to the states by the Fourteenth Amendment? Facts of the Case: The case of Wallace v. Jaffree calls into question the constitutionality of an Alabama statute that authorized teachers to lead a one-minute period of silence for â€Å"meditation or voluntary† prayer in all public schools. Ishmael Jaffree, the parent of three students in the Mobile County Public School system filed a complaint that twoRead MoreThe Slavery Of The United States1466 Words   |  6 PagesProtestant. This is reflected in early schooling, as many schools that children attended began the day with either prayers, readings from the King James version of the Bible, or some form of praising the Christian God. Over time, our country has shifted away from our devotion to religion. Because less people agree on religion in this country, and because public schools are government entities, as cases about religion and prayer in public schools have come up, religion has been separated from the schoolingRead MoreExpansion Of Federal Power : The United States1546 Words   |à ‚  7 Pagesincluding minimum wage and labor. The Court broadened the â€Å"Necessary and Proper† clause when it ruled that Congress can establish a federal bank. Finally, the Court reinterpreted the meaning of the First Amendment so as to eliminate voluntary prayer in public or in schools. These are not the only illustrations of the Supreme Court expanding federal power, but by examining these three examples, expansion of federal power is shown. The Commerce Clause was originally designed for congress to regulate commerceRead MoreSupreme Court Cases, Thematic Essay861 Words   |  4 Pagesthe case of Tinker vs. Des Moines School District (1969). 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A big part of the debate includes the EstablishmentRead MorePrayer In Schools Has Been A Much Talked About Debate In1434 Words   |  6 Pages Prayer in schools has been a much talked about debate in America over the past half-century. Conservatives, trying to regulate the religious freedoms of Americans , have tried numerous times to pass amendments that allow private student-led prayer in the classrooms(Baik, 243). Liberals, realizing that private prayer is and has always been legal, try to keep the balance between church-state separation as it is. This has kept the political issue of religion at a boil and confused many people on theRead MoreTeaching in America: God in Schools826 Words   |  3 Pagesinvolving teaching, including teaching in the government run public schools. Since the public schools are run by the government they have certain laws and restrictions that the teachers must abide by. One such law is influencing children to consider a certain religious belief during class time. Even though teachers in public schools are not allowed to mention their personal religion in the classroom, they can still share t heir beliefs after school or by fostering an atmosphere where the students ask forRead MoreThe Reflection Of Francis Bellamys Pledge Of Allegiance1092 Words   |  5 PagesAllegiance, an alteration that created an issue for a seemingly small amount of Americans, but an issue nonetheless. Americans from different religious backgrounds found that this inclusion infringed on their rights, especially in systems such as public schools, where the Pledge of Allegiance is recited daily. Expecting a person to recite god daily, who does not carry the beliefs of god is oppressing; the Pledge of Allegiance does this, therefore it oppresses a group of American citizens and should be