搜尋理論是訊息經濟學中很重要的一部份，搜尋行為有助於決策約滿意度。本文研究的重點主要在於商品市場上的消費者價格搜尋、消費決策及其與政府課稅之間的關係。 在消費者採用連續搜尋，而且假設搜尋不可回溯，搜尋次數有限，價格分配已知時，搜尋決策其有保留價格的性質。以「向後求解」的方法，消費者可以得到各期之保留價格。保留價格是稟賦所得、搜尋成本、其他財貨價格、效用函數及價格分配型態的函數。假設其他條件不變，若稟賦所得減少，搜尋成本增加，則保留價格上升；隨著已搜尋約次數增加，保留價格跟著上升，亦即消費者在搜尋過程中會愈來愈願意接受較高的價格。 消費者從事搜尋行為時的保留價格和搜尋成本會對消費決策產生影響。保留價格不但決定停止搜尋的時機，也會影饗真正從事購買的價格；可以用來消費的淨所得因搜尋次數的多寡而增減，所以等於也受到保留價格的影響。外生變數變動會改變保留價格，進而間接影饗預期需求，包括改變可接受價格之範圍和停止搜尋機率；然而，同時也會直接影響需求函數，總合上述兩者才能決定對預期需求的影響為何，結果通常使預期需求增減不易判別。預期搜尋次數與保留價格成反向關係。 政府對需要搜尋的財貨課從量稅，使價格分配向右平移，保留價格會隨之上升，但上升的幅度不會剛好等於稅率。稅率愈高，保留價格上升幅度愈大。平均而言，消費者因為租稅轉嫁必須支付較高的價格，所以會減少需求，此為課稅的直接影響；再加上提高保留價格而封預期需求產生間接影響，結果需求增減不易確定。在政府追求社會福利極大且受限於固定稅收之下，得到價格訊息不完全的最適租稅法則，比價格確定時多出了社會搜尋效果，包括課稅對願接受價格上下限和停止搜尋機率的影響，主要是透過課稅改變保留價格來達成。 假若效用函數為 Cobb-Douglas 的型態，價格呈一致分配，則由模擬方析結果發現，課稅後需搜尋財貨預期需求量減少，不需搜尋財貨預期需求量增加，預期效用降低且搜尋次數減少。

由人類學家所定義的互惠經濟之交易行為與我們所認知的市場交易相較之下有幾個特殊之處，如，強調交易雙方的關係、主觀的價值判斷等，近來經濟學家也嘗試以各種不同的角度（如：訊息經濟學、賽局理論、實驗經濟學、制度經濟學）來探討此一耐人尋味的交易行為， Kranton 的文章就是其中的一個代表。 Kranton 認為互惠經濟與市場經濟制度的差異僅是一些人們的心理偏好如：對財貨多樣性的偏好、對未來消費偏好上的程度大小之選擇問題，另外制度本身有一種「自我延續」的機能，任一種制度越被人們所青睞也就更確認其普行於社會的地位。他認為制度與制度之間存在著一種「競爭」的關係，社會最終只能容許一種制度存留，而結果取決於上述的偏好因素以及某制度開始時的起始值大小。 惟我們認為 Kranton 的模型有許多不完美之處，根據他的缺失，我們有了以下的補充及發揮。首先，從交易關係來瞭解交易行為，可以將兩種制度「互相競爭」的單一思考角度擴充到有「互補」可能性的思考空間。我們認為一項交易的完成不僅是客觀上財貨的交換，其他相關的事項如交易雙方藉由交易互動來達成訊息探測的目的及交易雙方的關係因為一連串的交易所發生的變化等都是值得我們注意的。我們會看見兩種不同的制度（互惠經濟與市場經濟）在同樣一項交易上運作乃是因為這兩種制度所詮釋的功能及範圍有所不同，彼此相互輔助而不一定有衝突發生。 第二、我們分別推演了「貨幣」、「法律制度」、「物品交換知識累積」等因素對互惠經濟轉變成市場經濟的可能性。我們發現「貨幣」的出現影響了因為以物易物所無法避免的一種「跨期交換」的人情債，但是貨幣也僅是影響其中一個「交易互動」的機會而已，新的互動機會可以不因為貨幣的出現而受到影響。法律制度對交易細節的強力背書，可省去交易雙方為了交易過程中可能發生的不確定性所額外必須做的「關係功夫」，但是真正令雙方滿意的交易仍需要交易當事者主動探尋求得。物品交換知識的累積代表人們將一些彼此之間的共識客觀成熟化，所以通常互惠經濟成熟後，市場經濟就會跟著出現。 最後我們認為「訊息」是互惠經濟能步入「市場經濟」的一個重要關鍵。一個人面對市場經濟多樣化的選擇時必須擁有充分的訊息作為選擇的依據，惟市場本身能衍生出另一種「訊息市場」來。在訊息提供上不僅要考慮到訊息的「廣度」也要考慮到「深度」，互惠經濟所形成的人際網路能透過「瞭解」的機制來傳遞及過濾「適當」的訊息，但是人際網路一樣會有「遞移成本」及「維護成本」的問題，另外訊息在消費上的不具敵對性會減低訊息市場上供給者的提供誘因，我們將以上的所有考慮因素具體化為一個簡單的模型，並試圖找出在訊息上提供上，互惠經濟與市場經濟之間的「分水嶺」。 / Reciprocal economy , compared to the familiar market economy,is characterized byseveral features such as gift giving,social structure patterns,subjective valuesRecently,economists try to explain such ambigious behavior by means of game theory, experimental methods,and institutional views.Kranton's paper is oneexample. From Kranton's point of view,reciprocal economy differs with market economyonly in poople's preferences such as preferences for diversity of goods,preferences for future consumption. In addition,institution itself has mechanisms of self-sustaining which guarantees its pervasion. That reciprocal economy is competitive with market economy means that only one institution can survivewhich is dependent on social preferences and institution's initial value. Not satisfied with Kranton's model, we try another way to handle the probleminto three parts. First,in views of transaction relationships,we may say that each institution'ssurvival is dependent on the other's persistence. Second, "money", "laws", and "transaction knowledge" are all important factors influncing the transition from reciprocal economy to market economy.Third,"information completeness "is a key factor of the market economy and the provision of information is another choice problem between reciprocal economy and market economy.

過去處理勞資雙方工資談判的文獻，多數假設勞資雙方的訊息是對稱的， 或採合作談判解，或採非合作談判解，他們得到結果多為工資協議往往非 常順利，不會有不合議的事件發生。但事實上勞資雙方談判時，公司的經 營能力或策略、工人之生產力往往是談判雙方互不了解的，也就是現實工 資談判中普遍存有訊息不對稱的情況。本文擬在訊息不對稱的情形下，假 設談判的一方訊息不完全--工會不了解公司的經營能力，設定一個兩期工 資談判模型，僅由工會提議工資，公司之反提議僅為接受或拒絕工會之提 議工資。探討模型之承諾均衡與完全貝氏均衡，並對影響完全貝氏均衡之 因素做進一步之探討。

本文以兩個眼動閱讀實驗探討語意訊息 (semantic cues) 和句法訊息 (syntactic cues) 如何在中文關係子句的處理中運作及交互作用。實驗一旨在研究兩種動詞與論元之間的合理性關係 (plausibility) 是否會影響讀者理解不同結構的關係子句。結果顯示，當兩個論元都是合理施事者 (agent) 時，論旨角色的指派 (thematic roles) 有歧義，較難理解；而當只有一個論元是合理的施事者時，讀者趨向指派正確的論旨角色，且較快整合句法上的困難。此外，因中文句法結構特殊，讀者在關係詞之前就處理主語關係子句 (subject relative clauses) 的歧義，在主要動詞上則會遇到賓語關係子句 (object relative clauses) 的理解困難。此發現解決了Hsiao & Gibson (2003) 和 Lin (2006) 的歧見，證明中文讀者在不同位置會遇到不一樣的困難。實驗二所關注的語意訊息為論元的生命性 (animacy)，關係子句中的兩個論元分屬有生命的 (animate) 及無生命的 (inanimate) 名詞。結果發現論旨角色的指派和生命性相互關聯，有生命性的論元較傾向當施事者，而無生命的論元傾向當受事者。讀者仍在關係詞之前遇到主語關係子句的理解困難，但在主要動詞，讀者主要依循生命性的引導來指派論旨角色，句法訊息的影響並不顯著。因此語意訊息在中文的語句處理扮演重要的角色，結果大致上與Traxler (2002)的研究相符。讀者同時受到當下的句法訊息以及語意訊息影響，在不同的位置會遇到不一樣的歧義性，而產生花園路徑效果 (garden-path effect)。 / Two eye movement experiments were conducted to investigate how semantic cues and syntactic structural cues function and interact in Mandarin Chinese relative clause (RC) processing. Mandarin Chinese is unique in combining head-final RCs with a VO basic order (Dryer, 1992, 2003) and also in relying solely on word order as structural cues, without case marking or agreement. However, Mandarin Chinese still preserves flexibility in word order that is motivated by pragmatics. Semantic cues, including the plausibility of the argument-verb relation and argument animacy within RCs, may be crucial to sentence processing in Mandarin Chinese. Experiment 1 aims to examine whether the meaning of the verb allowing only one of the two animate arguments to be a plausible agent may lead to reduction of ORC difficulty (cf. Traxler, 2002). The results showed that the plausibility effects were robust at the head noun and the main verb. A bias of thematic role assignment in the irreversible relation leads readers to correct interpretations, while the reversible relation does not elicit such a bias. The results also solved the discrepancy between the two previous studies (Hsiao and Gibson, 2003 & Lin, 2006) by unveiling a dynamic process in which readers encounter diverse ambiguities at different positions for different structures. Chinese readers disambiguate SRCs earlier due to their non-canonical word order and have trouble integrating the main verb in ORCs owing to perspective shifting. The interaction between plausibility and RC type on re-reading rate suggested that plausibility cues were used to solve syntactic ambiguity. Experiment 2 manipulated contrastive argument animacy in order to investigate whether thematic role assignment correlates with animacy. The results confirmed the hypothesis that while animate entities bias towards agent roles, inanimate ones incline towards patient roles (c.f., Valin & LaPolla, 1997). Besides, inanimate entities are conceptually less accessible than animate ones. Contrastive animacy shows its impact on syntactic processing with robust interactions at different positions. The findings of interactions between semantic cues and RC types in two experiments suggest that semantic cues play an important role in Chinese relative clause processing. Semantic plausibility and argument animacy can influence the process of thematic role assignment. The semantic cues that accord with the biases of thematic role assignment then would ease the syntactic ambiguities. Not only syntactic cues but also semantic cues are utilized by readers in sentence comprehension. In this thesis, the eye movement data provide clear evidence indicating that readers solve various temporary ambiguities syntactically and semantically at different positions of the sentence with relative clauses.

本研究係以裁量性應計數字及其組成成分衡量盈餘管理，以審計人員產業別市場佔有率與產業別客戶集中度之綜合衡量捕捉審計品質，探討不同樣本公司之盈餘管理特性，以及審計品質對不同盈餘管理特性之影響。管理者對應計項目的認列通常有某種裁量權，此裁量權可用以顯露私有資訊而增進盈餘的價值攸關性，或可投機性地管理盈餘而減低盈餘為公司績效衡量的可靠性。所以探究盈餘管理行為是增加財務報告資訊性(information)或雜訊(noise)即非常重要。研究內容依盈餘管理特性區分為投機性盈餘管理與訊息發放性盈餘管理二大部分。每一研究內容則是先辨認盈餘管理本質，其次探討審計品質對盈餘管理之影響。在研究設計上，為避免實證代理變數之衡量誤差重大影響結果，乃採用實驗組公司與控制組配對公司相比較，以凸顯出前者之盈餘管理型態。 　　研究結果顯示，門檻公司從事盈餘管理以達前期盈餘門檻，且此盈餘管理不具未來現金流量持續性之涵義，係符合「隱藏當期不利績效、遞延本期不尋常盈餘至未來年度」以減低會計盈餘數字波動性之特性。就自願性盈餘預測此一資訊揭露工具而言，在盈餘預測偏屬樂觀之傾向下，仍有管理者自願揭露壞消息預期，即可知管理者之誠意，不失為一可資信賴之訊號。但自願預測盈餘增加，則不必然具有高公信力。甚至在管理者降低盈餘差距之動機下，易引起管理者操縱盈餘。此為財務報表使用者所需注意。就持股變動此一資訊揭露工具而言，在我國家族企業居多之情形下，增加持股並未代表任何特定之涵義。反而是減少持股所透露之訊息，值得投資人注意，尤須慎防其盈餘操縱行為。 　　面對增加所得之裁量性應計數字，審計品質有效阻止投機性盈餘管理。面對顯露私有資訊之盈餘管理，審計品質能夠協助管理者選擇最能彰顯未來現金流量預期之會計方法，以增強裁量性應計數字與未來現金流量變動之關聯性。在高審計品質所賦予之資訊公信力下，盈餘資訊在投資人之決策過程中有一定之重要性，故投資人發現裁量性應計數字增加（減低）盈餘價值攸關性，因而增加（減低）盈餘評價係數。然而對低審計品質所查核的財務報表，較低的資訊公信力，使盈餘未在投資人評價過程中扮演重要角色，因而盈餘管理特性亦不受投資人重視。 / This research examined characteristics of earnings management and effects of audit quality therein. Specifically, the magnitude of earnings management was proxied by the discretionary accruals, which are estimated using a cross-sectional version of the Jones model. Different from prior research, the audit quality was captured by a combined measure of the auditor's market share and client concentration. The market share measured the auditor's competence (industry specialty) and the client concentration measured the auditor's independence. Managers usually exercised discretion to recognize accruals. They could either signal private information to enhance earnings' value relevance, or opportunistically manage earnings to reduce the reliability of earnings as the performance measure of the firm. As a result, it was important to examine earnings management and to identify whether it would increase the informativeness or noise of financial reports. This study was organized according to the characteristics of earnings management: opportunistic earnings management and signaling earnings management. For both parts, the nature of earnings management was identified first, and then the effects of audit quality therein examined. To reduce the impact of measurement errors of proxy variables, the treatment group and controlled group were compared and contrasted to make earnings management pattern of the treatment group more evident. 　　The results showed that threshold firms managed earnings to sustain last year's earnings level. Discretionary accruals of the threshold firms were not significantly associated with future cash flow changes. Those discretionary accruals were used to hide the current unfavorable performance, or to defer current unusual earnings to the future, so that managers could reduce the volatility of accounting earnings. As a means of information disclosure, voluntary earnings forecasts tended to be optimistic, but we still could observe some voluntary forecasts which decreased earnings. In those situations, we might conclude that managers tried to convey credible signals. However, it was not necessarily credible in the case of voluntary forecasting which increased earnings. Managers would manipulate earnings to reduce the difference between forecasted earnings and reported earnings. In respect of the information signal of changes in directors' share holding percentages, it signaled nothing when directors increased holding percentages because most companies were family businesses in Taiwan. Nonetheless, investors should look out the possibility of earnings manipulation when directors decreased their holding percentages. 　　Audit quality could effectively deter opportunistic earnings management but not the income-decreasing discretionary accruals. Based on information signaling perspective of earnings management, auditors with higher audit quality tended to assist managers to choose accounting methods that might signal cash flow expectations. Stronger associations between discretionary accruals and future cash flows were observed for firms audited by higher quality auditors. Because higher audit quality might increase information credibility, earnings would play a more important role in the decision process of investors. When discretionary accruals increased (decreased) earnings' value relevance, earnings association coefficients would be increased (decreased). However, for the financial reports audited by lower quality auditors, earnings did not play an important role in the valuation process because of lower information credibility. Therefore, empirical results showed that investors of firms audited by lower quality auditors did not make decisions according to different characteristics of earnings management.

在傳統的簽章機制中，我們需要一個具有公信力的第三方 (Trusted Third Party, TTP) 來核發數位憑證，以驗證公開金鑰確實屬於簽章者所擁有，為了減少TTP的負擔，於是就有學者提出了免憑證簽章 (Certificateless Signature) 機制。另一方面，具有訊息回復 (Message Recovery) 功能的數位簽章是指原始訊息不需要與簽章一起傳送給接收者以簡化訊息及簽章在傳送時的長度。 本論文中我們提出了一個具有訊息回復功能的免憑證簽章機制，和一般簽章方式相比，我們的方法不僅具有免憑證簽章的優點，訊息回復功能也減少了訊息和簽章的總長度，提昇了訊息的傳送效率 (Communication Cost)，在效能方面也有不錯的表現，因此非常適用於以頻寬為主要考量的公司組織以及對短訊息作簽章的應用，最後我們也有對我們的簽章方法做完整的安全性證明。 / In traditional digital signature systems, a trusted third party (TTP) is required in order to issue a digital certificate. The certificate is to assure that the public key actually belongs to the person of the signature. In order to reduce the burden of TTP, some scholars proposed the Certificateless Signatures. On the other hand, a digital signature with message recovery is a signature that the message itself is not required to be transmitted together with the signature. It has the advantage of small data size of communication. In this paper, a certificateless signature with message recovery is proposed. It inherits both the advantages of certificateless signatures and signatures providing message recovery. The performance of our scheme is compared with other schemes which shows that our scheme is quite efficient and the security of the scheme is finally proved in the random oracle model.

句子的主題具備了串連訊息、引導文句發展的重要功能，然而資料顯示許多外語學習者常因為使用不適當的主題而影響語句的連貫性以及文章的流暢度。本研究透過觀察台灣高中生記敘文的主題類型，分析其在高、中、低分群學生文章中的使用情形來了解主題的選用對文章連貫性以及整體作文品質的影響。 本研究分成初步試驗以及正式研究兩階段，在初步試驗階段我們建立了分析的架構。在正式研究階段，我們採集111位高三學生於課堂上完成的記敘文並交由兩位經過訓練的閱卷老師進行評分，最後結果產生高、中、低分三組學生作文，接著再從每一組的文章中各抽樣10份進行主題類型之分析研究。 分析結果顯示，三組學生作文的主題類型及出現頻率大致雷同，整體而言，學生最喜好使用非標記的名詞主題，卻最少使用標記的分詞+名詞主題。然而進一步分析三組的主題發展情形，卻發現有顯著的組別差異，以高分群為例，其主題多具備銜接上文或有利推進文意的背景資料文字，相較之下，中等或低分群的作文比較容易出現和上下文不相關或中斷文意發展的新主題。 根據本研究的發現，我們建議在英語作文課中介紹句子主題的概念，幫助學生熟悉其類型和功能，期使學生能在記敘文文章中正確使用主題來達到語句連貫，文意流暢的溝通目標。 / Theme plays a significant role in guiding the information flow in text. Nonetheless, there is evidence indicating that many EFL learners often fail to make good choices of theme to secure sentential relationship or writing coherence. Through the observation on the occurrences and distribution of theme types in three levels of student compositions: the high, the middle and the low-rated narratives, the present study aims to investigate the establishment of theme in Taiwanese senior high school students’ narratives in order to gain understanding of theme’s effect on writing coherence and writing quality. The entire study consists of a pilot study and a formal one. The pilot study helps establish the criteria for the main study. In the main study, 111 student compositions were gathered and two raters were recruited and trained for the rating. Based on the rating system, the student compositions are divided into 3 levels. 10 samples from each level were randomly selected for thematic analysis. The result shows that the occurrences and distribution of theme types in the three levels of writing are alike. In general, unmarked NP theme is the most favored by all the students and marked theme Non-fi C + NP is the least desirable. Nonetheless, in terms of the establishment of theme, there are major differences between groups. In particular, the high-rated essays tend to establish a theme that is connected to the theme or the rheme in the preceding discourse or provides background information for the development of the event. In contrast, the mid-or low-rated essays are more likely to establish a theme that is unrelated or disruptive to the progression of the current discourse. Based on the findings of the present study, it is suggested that the notion of theme including its features and functions be incorporated into the teaching of English compositions to help Taiwanese senior high school students identify the characteristics of coherent writing and facilitate coherence in their English narratives.

本論文共分為六章。第一章旨在概略介紹本論文之基本理念與架構，俾使讀者能初步瞭解本論文題目之爭點所在。 第二章針對內線交易在立法政策上應否予以禁止之議題，本章首先將釐清內線交易之基本內涵，並具體闡述內線交易對社會及經濟等各層面所帶來的影響與危害，以期對內線交易首先建立一個宏觀印象。進而分別從經濟與法律兩個不同層面，彙整不同學派提出之見解，並針對各種論調提出本文想法。最後說明我國對內線交易採取之立法政策及規範意旨。 第三章以美國法院判例之演變為討論中心，美國判例法下之內線交易理論歷經幾十年之建構與變動。最早在法制規範前，法院採取普通法下特殊情事理論作為禁止內線交易之論據；其次發展出「公開否則戒絕交易原則」，繼而逐漸延伸出「傳統信賴關係理論」、「訊息傳遞責任理論」以及「私取理論」，依據實際規範需要而對於內線交易行為主體範圍作適度地限縮與擴張。本章主要目的即在於，藉由詳細地分析美國判例法上深具代表性之案例，以及各種內線交易理論基礎之構成理由，進一步釐清內線交易行為主體之射程與規範現狀。另外亦將透過各種交易關係模式之分析，檢視理論之間的協調性，並提出本文意見。 第四章介紹「歐洲內線交易行為主體之規範」。1989年歐洲部長理事會頒佈《歐洲共同體內線交易協調指令》（89/592/EEC），此項指令列出內線交易規範之最低標準，要求其會員國在1992年7月1日前完成國內法之制訂，以實現指令規範內線交易之目標。2003年《內線交易及市場操縱之指令》（2003/6/EC），更針對現有內線交易指令進行修正，並新增市場操縱行為之規範，以取代89/592/EEC號指令。本章之目的，即在於介紹歐洲共同體針對內線交易行為主體之規範內容，進而探討內線交易之規範基礎。 第五章首先對於我國內線交易之規範作一概略性之介紹，並從規範架構探討我國內線交易理論之取向。第二節次就我國內線交易行為主體之規範範圍進行分析，並進一步探討理論與規範在實際應用上是否協調一致，抑或相互矛盾。第三節則歸結前兩節所論述之爭點，提出完整之規範建議。 第六章主要在於彙整前面各章之重點，並再一次強調本文立場與建議。

預測市場的研究近年來在學界逐漸受到重視，因為它利用價格具有訊息加總的功能，每每創造出良好的預測績效，但一個預測市場的建立在諸多原因下，通常不易吸引大規模的參與者，例如為免觸犯法令規定，以虛擬貨幣代替真錢進行交易，在缺乏真實貨幣的獲利誘因下，很難有效吸引參與者，即便真能以真實貨幣交易，若實驗的議題並非一般大眾感興趣的話題也不易吸引多數人參與，在這種情況下無法避免要面臨市場交易過於淺薄的問題，雖然不少文獻標榜淺薄市場不會影響預測市場的預測精準度，但並不表這是一個可以置之不理的問題。 本文以預測市場預測2006年北高市長選舉為實證基礎，闡明淺薄市場對價格產生的影響，以及這些影響將導致對未來事件的錯誤評價與推論，要避免這種錯誤的評價與推論唯有設法消除淺薄市場引發的干擾，因此我們提出了五種可以消除這些干擾的方法並從中選擇一較佳者。如同一般文獻的讚揚，我們再次從預測市場獲得精確的預測效果，同時證明所謂淺薄市場不影響預測市場的預測精準度前提乃在消除淺薄市場對價格產生的干擾之後才能還原這個真相。

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.