本研究利用台灣2001年資料以Ramsey與OLG假設分別建立區分四部門別與八部門別之動態可計算一般均衡模型，進行「提高間接稅（消費稅、環境稅）、降低直接稅（資本、勞動所得稅）」之稅制改革模擬分析。結果發現若以單一時點比較靜態方式分析可能迥異於動態長期分析結果；其次以Ramsey分析所欠缺的代際分配影響結果在OLG分析中可以察見，特別是進行以消費稅或環境稅替代資本所得稅模擬時；再者OLG因代際傳遞效果可能較Ramsey假設下反應緩慢，故也可觀察到Ramsey模型面對衝擊後若干變數增減幅度會較OLG模型陡峭。最後特別在環境稅替代所得稅模擬中經由替代稅率變化發現，活在初期世代雖可享受所得稅下降好處但卻也面臨排放稅課徵，因此福利水準增減變化不大，惟屆至排放稅課徵瀕至臨界點需使用原所得稅來平衡稅收時，此為另一波必須為減量政策付出代價的時點與世代。 / Based on a thorough comparison of the basic assumptions and economic underpinning of the Ramsey and Overlapping generation (OLG) model, this study builds both static and dynamic computable general equilibrium tax policy models to analyze the effect of tax reform on Taiwan’s economy. The new tax structure considers mainly a replacement of some parts of direct tax - labor and capital income taxes by indirect tax- consumption tax or environment tax. The benchmark year of the model is 2001, and the economy is divided into four and eight sectors. The modeling framework is implemented on top of MPSGE, which is a special module within the General Algebraic Modeling System (GAMS).Our simulation results show differential outcomes for static and dynamic models. The slower speed of transition inherent in OLG model has caused variables such as welfare, capital stock, and replacement consumption tax rate change less than that in the Ramsey model when the tax reform policy is imposed. And the intergeneration effects of different tax burden between young and old generations can be found in the OLG model but not in the Ramsey model. Finally, we find as the income tax rate coming lower and the environment tax going up when simulation of tax replacement, causing the welfare does not change much at the beginning of shock, and generations especially born in the near future when environment tax does not grow and revenue neutrality needs to be meet are another cost payers of abatement policy.

The existence of sunspots or sunspot equilibria has been debated for several decades on its influence in the field of Economics. While models of sunspots or sunspot equilibria have fitted well for some subsets of empirical features, it comes at a cost of moving further away from economic believability and robustness. Studies on the theoretical plausibility of sunspot equilibria have been addressed extensively in several different economic models, but exist almost entirely within the framework of the homogeneous rational expectations equilibrium devised of representative agents. This framework shapes later arising learning approaches to sunspot equilibria. These models have proposed various ways of learning, but they deal mainly with the learning of representative agents. Models of adaptive learning with heterogeneous agents, however, enable us to explicitly tackle coordination issues, such as the coordination mechanism of expectations. This is certainly desirable since sunspots are often used as a coordination device of expectations. In this dissertation, we continue this line of research, investigating the plausibility of sunspot equilibria in stock markets within the framework of heterogeneous agents and the dynamic relationship between sunspot variables and stock returns. We adopt an Agent-based Computational Approach, now known as Agent-based Computational Economics or ACE, to study the plausibility of sunspot equilibria. More specifically, we deal with this issue in the context of an Agent-based Artificial Stock Market (AASM). We contemplate AASMs to be highly suitable to the issue we examine here. Currently, none of the theoretical, empirical, experimental, or simulation models of sunspot equilibria directly capture sunspots within a stock market composed of heterogeneous agents. We conducted three series of experiments to examine this issue. From the results of these three series of simulations, we observed that sunspot variables generally do not have influence on market dynamics. This indicates that sunspot variables remain largely exogenous to the system. Furthermore, we traced the evolution of agents' beliefs and examined their consistency with the observed aggregate market behavior. Additionally, this dissertation takes the advantage of and investigates the micro-macro relationship within the market. We argue that a full understanding of the dynamic linkage between sunspot variables and stock returns cannot be accomplished unless the feedback relationship between individual behaviors, at the micro view, and aggregate phenomena, at the macro view, is well understood / The existence of sunspots or sunspot equilibria has been debated for several decades on its influence in the field of Economics. While models of sunspots or sunspot equilibria have fitted well for some subsets of empirical features, it comes at a cost of moving further away from economic believability and robustness. Studies on the theoretical plausibility of sunspot equilibria have been addressed extensively in several different economic models, but exist almost entirely within the framework of the homogeneous rational expectations equilibrium devised of representative agents. This framework shapes later arising learning approaches to sunspot equilibria. These models have proposed various ways of learning, but they deal mainly with the learning of representative agents. Models of adaptive learning with heterogeneous agents, however, enable us to explicitly tackle coordination issues, such as the coordination mechanism of expectations. This is certainly desirable since sunspots are often used as a coordination device of expectations. In this dissertation, we continue this line of research, investigating the plausibility of sunspot equilibria in stock markets within the framework of heterogeneous agents and the dynamic relationship between sunspot variables and stock returns. We adopt an Agent-based Computational Approach, now known as Agent-based Computational Economics or ACE, to study the plausibility of sunspot equilibria. More specifically, we deal with this issue in the context of an Agent-based Artificial Stock Market (AASM). We contemplate AASMs to be highly suitable to the issue we examine here. Currently, none of the theoretical, empirical, experimental, or simulation models of sunspot equilibria directly capture sunspots within a stock market composed of heterogeneous agents. We conducted three series of experiments to examine this issue. From the results of these three series of simulations, we observed that sunspot variables generally do not have influence on market dynamics. This indicates that sunspot variables remain largely exogenous to the system. Furthermore, we traced the evolution of agents' beliefs and examined their consistency with the observed aggregate market behavior. Additionally, this dissertation takes the advantage of and investigates the micro-macro relationship within the market. We argue that a full understanding of the dynamic linkage between sunspot variables and stock returns cannot be accomplished unless the feedback relationship between individual behaviors, at the micro view, and aggregate phenomena, at the macro view, is well understood.

本文建立一個小型開放經濟的內生成長模型，並且以貨幣進入生產函數的方式，將貨幣引入經濟體系。據此，我們分別探討勞動外生及勞動內生的狀況下，央行以釘住通貨膨脹率作為貨幣政策，民眾的信念是否可以造成景氣的波動，並探討央行採行未預料到的貨幣政策及預料到的貨幣政策會如何影響經濟體系相關變數的成長率。 　　根據本文的分析，我們發現在勞動外生的狀況下，通貨膨脹率與Tobin q值呈現負向關係，由此我們可以推論，提高通貨膨脹率目標將對經濟成長率造成負面的影響。當央行採取通貨膨脹率指標作為貨幣政策時，經濟體系呈現均衡的確定性，表示民眾的信念不會造成景氣的波動。若央行調整通貨膨脹率目標時，名目貨幣供給成長率和通貨膨脹率呈現不同比例的變動，且變動方向不確定，需端視實質餘額成長率下降的效果與通貨膨脹率調整的效果何者較大才可決定。在政策宣示的部分，宣告期間的長短僅影響經濟成長率、實質資本成長率及實質貨幣餘額成長率的跳動幅度，不影響動態調整路徑的形狀。 　　在勞動內生化的狀況下，通貨膨脹率增減不影響Tobin q值的變動，故提高通貨膨脹率目標不會影響經濟成長率。當央行採取通貨膨脹率指標作為貨幣政策，勞動需求線斜率大於勞動供給線斜率時，經濟體系呈現均衡的不確定性，表示民眾的信念可以造成景氣的波動在央行調整通貨膨脹率目標時，名目貨幣供給成長率和通貨膨脹率呈現同方向、同比例變動。最後，政策宣示部分，政策宣告期間的長短會造成經濟成長率、實質資本成長率及實質貨幣餘額成長率呈現不同的動態調整路徑。

本文建構一個小型開放的經濟體系，價格具有僵固性的 DSGE 模型來探討提早釋出的關稅調降訊息所造成總體經濟面的影響。在政府簽訂貿易協定來降低關稅的訊息藉由媒體釋出時，同時民眾具理性預期的假設下，家計單位會因這樣的訊息而改變對未來的預期，在關稅還未實際調降時便改變行為決策。我們研究在不同的協商可能結果: (1)談判破裂，貿易協定未如預期簽訂。(2)談判成功，但貿易協定簽訂的結果比當初訊息所透露的降得更多或較少。(3)談判成功，並完全實現當初訊息的內容。(4)簽訂的時間高於預期，導致實行的時間延期。從結果中我們發現，提早釋出的關稅訊息會抑制民眾的消費和投資，在短期會立即造成需求面的負向衝擊。而降低關稅所帶來的市場活絡，會等到真正調降的時後才出現。所以越早釋出關稅調降的訊息，會造成經濟體系所需付出“等待政策實行的成本”越大。 / There is global trend of economic integration across the world by removing the trade barrier. While the free trade agreements normally include the tariff reduction, the negotiations of the agreement may take a long time, and in some cases, the negotiation may fail. Therefore, the tariff reduction’s effects on the economy can be different if it is realized as expectation or not. With a small open economy DSGE model, this paper examines the effects of news preannouncement on tariffs. With the assumption of rational expectation, households will change their expectation when the news of tariff decrement is preannounced. However, whether or not the news on tariffs can be realized as expectation will lead to different dynamics. In this study, we consider various plausible scenarios: (1) If negotiation fails, thus the news on tariff reduction is not realized (2) If negotiation succeeds, but the amount of actual decrement is more or less than people originally expected. (3) Negotiation succeeds and the content of news is fully realized. (4) Negotiation succeeds, but it takes more time than expected to be realized, thus the policy implementation is postponed. Our study reveals that the news preannouncement restrains consumption and investment before the negotiation is completed, and leads to a negative impact on the economy in the short run. The benefits of the tariff decrement appear if the policy is actually implemented as expected. However, the economy suffers more if the negotiation takes too much time after the news is released.

浮雕是雕刻藝術中重要的表現方法，藉由在平板上雕刻出高低落差，傳達出豐富的形狀視覺線索，是介於3D雕塑和2D畫作中間的一種物體外形的表現方式。本論文將針對淺浮雕這類型相對高度較低的浮雕技法，將要表達的3D場景壓縮到接近平面但盡可能保留細節。我們使用適應性直方圖均衡化技術去壓縮高度的動態範圍並盡可能強化細節，且經由降低取樣點數量的技巧加速適應性直方圖均衡化的計算，以利於使用者進行互動性自訂風格化。另外依照場景特徵的流向，增加特殊的刻紋去豐富淺浮雕的風格表現。 / Relief is a sculptural technique to express the shape feature on a flat surface. It is an art medium between 3D sculpture and 2D painting. In this thesis, we focus on bas-relief, which is a relatively low relief to compress the depth of 3D scene to a shallow overall depth and preserve details of the shape. We use the adaptive histogram equalization (AHE) to compress the depth range and enhance details, and accelerate the AHE computation by sample reduction, which is in favor of the user interaction of custom stylization. Furthermore, adding special carving patterns according to feature flows of the scene enriches the stylization of the relief generation.

本文首先構建了在完全資訊下的異質分群模型。當玩家可以觀察其他玩家的類型，則均衡必定是非隔離的：大多數玩家將無意移動，這是因為他們的夥伴可以為他們帶來最好的報酬。均衡狀態將會是一個有效率的狀態。     然後，我們構建另一個分組模型:訊息不完全和雙重改變下的分群模型。結果表明，雖然非隔離的均衡有可能是在短期的穩定均衡，但只有隔離的均衡狀態可以在長期維持穩定。這是因為在長期下，大多數非隔離狀態可以輕易地切換到隔離狀態的緣故。 / This paper first constructs a grouping model with heterogeneous population under the setting of complete information. When player can observe other's type, the result isnon-segregation: most players have no intention to move and they can match with the one who brings them the best payoff in the original group. The equilibrium state is always efficient. We then construct another grouping model with incomplete information and double mutation. The result shows that, although non-segregation equilibria may emerge as stable equilibria in the short run, only segregation equilibria can be stochastically stable in the long run. This is because most of non-segregated states can switch to the others by the same re-sistance and some of them can easily switch to segregated state, but it is hard to switch back.

本研究建立含資產價格泡沫的隨機動態一般均衡 (Dynamic Stochastic General Equilibrium, DSGE) 模型，並以此討論貨幣政策與總體審慎政策的效果。泡沫存在於不動產的股票價格上，且不動產與一般資本皆為生產要素。研究顯示，在隨機衝擊下，一般資本的投資與不動產投資呈現負相關。融資擔保率的調控為總體審慎政策的範疇，本文另研究融資擔保率對經濟變數的影響。結果顯示，當擔保率調升時，產出增加、泡沫減少且不動產的股價 (資產價格) 下跌。本文亦討論依循泰勒法則下的貨幣政策與總體審慎政策對產出與資產價格波動的影響；結果顯示，在經濟景氣時實施緊縮貨幣政策可同時減少資產價格與產出的波動，其效果優於總體審慎政策。 / This study established a Dynamic Stochastic General Equilibrium (DSGE) model, which contains asset bubble price, and employed DSGE to discuss the effect of the monetary policy and the macro-prudential policy. Bubbles exist in the stock price of the real estate. Real estate and general capital are both the factors of production. The study indicates that, under stochastic impulse, a negative correlation exists between the investment of the general capital and the investment of the real estate. The study also discusses the operation of the collateral rate, a perspective dealing with macro-prudential policy, and how it influences economic variables. The results present that when collateral rate rises, output increases, bubbles decreases and the stock price of real estate (asset price) declines. The study further investigates how monetary policy, which follows the Taylor rule, and macro-prudential policy affect the vibration of the output and the asset price. The result indicates that during economic prosperity, the implementation of tight monetary policy presents better effect than that of macro-prudential policy since it simultaneously decreases variances of output and asset price.

在面臨2008年金融危機後嚴峻之需求面衝擊下，多國央行紛紛調降利率，甚至調降至零利率，以期望國家能盡速脫離經濟衰退。在利率調降的過程中，由於受零利率下限的限制，單純藉由傳統貨幣政策之調控，仍可能無法使經濟從嚴峻的需求面衝擊下恢復。因此，非傳統貨幣政策也在美國、日本、英國、歐元區等國家被央行所採行做為對抗經濟衰退的政策工具。在此背景下，我們想了解如何實施最適非傳統貨幣政策。 在最適貨幣政策理論發展中，最適傳統貨幣政策發展較早，因此也較為完備。而在最適非傳統貨幣政策方面，前瞻指引(forward guidance)這項政策工具已被引入最適理論中來進行討論，但量化寬鬆(quantitative easing)直至今日還未被引入最適理論中來討論。 因此，本文建構一個封閉的新興凱因斯模型(New Keynesian)，開創性的將量化寬鬆引入最適貨幣政策理論中，來討論最適傳統與非傳統貨幣政策，也藉此與過去文獻比較施行量化寬鬆與未施行量化寬鬆之影響。 / After financial crisis occurred in 2008, countries, such as United States of America, United Kingdom, Japan and the euro area, have been mired in slow economic growth, compared with long-term, and have confronted with severe negative demand shocks which can’t be offset by zero interest-rate policy. Under the circumstance where zero lower bound was present, unconventional monetary policy was implemented by central bank of each country to end up the economic recession prospectively. As a result, we are interested in how to implement optimal unconventional monetary policy. The literatures regarding implementing conventional optimal monetary policy under demand shock were developed maturely. Forward guidance, one of unconventional monetary policy, was already developed in field of optimal monetary policy under impacted by demand shock, but quantitative easing has not been conducted in the theory of optimal monetary policy so far. Thus, we construct a close-economy by New Keynesian model to conduct quantitative easing into the theory of optimal monetary policy to discuss the optimal conventional and unconventional monetary policy, and to compare the difference corresponding to the previous literatures which without quantitative easing.

京都大学 / 新制・課程博士 / 博士(理学) / 甲第24427号 / 理博第4926号 / 新制||理||1703(附属図書館) / 京都大学大学院理学研究科地球惑星科学専攻 / (主査)教授 宮﨑 真一, 准教授 西村 卓也, 教授 王 功輝 / 学位規則第4条第1項該当 / Doctor of Science / Kyoto University / DGAM

本文的研究目的為，在一個含有房屋及房屋相關貸款的動態隨機一般均衡模型的架構中，比較貨幣政策、財政政策以及總體審慎政策對於房屋價格及房屋相關貸款的穩定效果。本文建構一個經濟封閉體系，其中包含三種不同家計單位、商品生產部門、房屋建商、資本生產部門，並且由政府部門制定相關政策；此模型的特色為，不同家計單位中的借貸行為、名目價格僵固性以及透過房屋價格抵押貸款的限制來刻劃金融摩擦。我們考慮了一般緊縮貨幣政策、提高財產稅率以及緊縮貸款價值比；本文發現，在三種政策中，對於抑制房屋價格以及降低住房貸款對國內生產毛額的比例，財政政策及總體審慎政策比起緊縮貨幣政策擁有較好的效果。 / The main purpose in this paper is to compare the effect of monetary policy, fiscal policy and macroprudential policy on housing price and housing related loans using a micro-based dynamic stochastic general equilibrium (DSGE) model with housing and housing related loans. We equip a closed economy model with three types of infinitely-lived households (patient households, impatient households and renters), a goods firm, housing and capital producer and a government sector. The model features borrowing and lending between patient and impatient households, nominal rigidity in goods price and financial friction in the form of collateral constraints tied to price of house. We consider the contractionary monetary policy by raising the interest rate, fiscal policy by increasing property tax rate and the macroprudential policy through tightening the loan-to-value (LTV) ratio. We find that among these three policies, in terms of dampening the price of housing and lowering the loan-to-GDP ratio, raising the property tax and lowering the LTV ratio outperforms the contractionary monetary policy.