Author: uniquekey

  • newsletter (July 2021 – Issue 10)

    newsletter (July 2021 – Issue 10)


    關於香港桂冠論壇



    歡迎大家來到香港桂冠論壇2021年7月份通訊。

    現時,首屆香港桂冠論壇(簡稱「桂冠論壇」)將延期一年至2022年11月,但是我們在促進不同世代、文化和領域的科學家互相交流;提升年輕一代對不同科技領域的認識和興趣等使命的工作是不會慢下來的。香港桂冠論壇委員會The Council of the Hong Kong Laureate Forum Limited(簡稱「論壇委員會」)現正籌備一系列「首屆論壇前奏活動」,繼續努力加強世界各地青年科學家的聯繫;並且積極迎接首屆桂冠論壇的來臨。活動包括有展示香港科研成果的 “Science Exposition”、與世界知名科學家進行研討會和對談的 “Masterminds, Masterclasses”、實地了解有作為的科學家工作的”Exploring New Horizons”、展示和表揚女性在科學方面的貢獻,從而啟發更多女性投身科學的 “Wonder Women in Science – Inspiring and Empowering the Next Generation”,以及為首屆香港桂冠論壇打開序幕的發佈會”Beckoning the Inaugural Hong Kong Laureate Forum”。

    另一方面,我們的網上遊戲「牠和它的名字 他和她的姓氏」遊戲已經在7月9日完滿結束,兩輪遊戲中我們一共收到超過70份作品,在綜合評審團的評分以及在Facebook超過800人次的投票後,各獎項的得獎者都是實至名歸的,他們的作品都是十分有趣和具吸引力。再次恭喜今次遊戲的一眾得獎者,他們亦很高興領取了獎品。在此特別鳴謝為遊戲評分的三位評審,他們分別是︰

    – 香港天文台前台長岑智明先生, SBS
    – 香港中文大學湯兆昇博士
    – 香港浸會大學何觀陞博士

    論壇委員會會繼續舉辦有趣生動及資訊性質的科學遊戲,在社區層面推廣科學發展。

    更多有關「首屆論壇前奏活動」和科學遊戲的資訊,歡迎留意我們的網站和社交媒體!

    最後,邵逸夫獎基金會已於2021年6月1日舉行的新聞發佈會上公佈了2021年度邵逸夫獎得獎者名單。

    天文學獎平均頒予加拿大麥吉爾大學的維多利亞•卡士比教授和美國喬治華盛頓大學的赫里莎•庫韋利奧圖教授以表彰她們對理解磁星作出貢獻。磁星是一種高度磁化的中子星,與很多壯觀的瞬變天體物理學現象有關。她們開發了新穎和精確的觀測技術,從而證實具有超強磁場的中子星存在,並描繪出它們的物理特性。她們已將磁星確立為一種嶄新而又重要的天體物理物體。

    生命科學與醫學獎頒予美國康奈爾大學的斯科特•埃姆爾教授以表彰他所發現的內體蛋白分選轉運複合體 (ESCRT) 途徑,對於涉及膜生物學的多樣化過程至關重要,其中包括細胞分裂、細胞表層受體調節、病毒傳播及軸突修剪等。這些過程對於生命、健康及疾病尤其重要。

    數學科學獎平均頒予法國巴黎第十一大學的尚—米歇爾•比斯姆教授和美國紐約大學的傑夫•奇格教授以表彰他們對幾何學的貢獻。他們非凡的見解改變了現代幾何,其影響歷久彌新。

    恭喜5位2021年邵逸夫獎得獎者!2021年度的頒獎禮將會再次以虛擬形式,於今年10 月在網上舉行。有關資訊,請留意邵逸夫獎和我們的網站和社交媒體!


    香港天文台的早期歷史



    建立天文台的需要

    香港在1841年開埠以來,不斷發展成為一個重要的貿易港口,要確保港口運作暢順和船隻航行安全,首先必須提供準確的報時服務。在上一期的《香港桂冠論壇通訊》,香港天文台前台長岑智明先生談到觀象授時對航海的重要性,尤其是在海上需要一個準確時鐘來測定船隻的經緯度。早在1861年,香港社會已經有意見認為當時以鳴炮報時的服務不準確,提議設立一個以科學方法提供的準確報時服務。

    香港位於華南沿岸,每年5月到11月都可能受颱風侵襲。早在18世紀外國人在廣州黃埔港和十三行進行貿易時已經對颱風的影響有詳細記錄。當英國人在1841年佔領香港不久,於同年7月已經感受到颱風的威力,在第一次鴉片戰爭中舉足輕重的英國海軍司令伯麥(Gordon Bremer)和香港第一任行政官義律(Charles Elliot)幾乎在1841年7月的颱風中喪命。到了1874年9月,史稱「甲戌風災」的猛烈颱風在香港和澳門造成嚴重傷亡 ─ 香港死亡人數超過二千,而澳門死亡人數更達五千,佔當時人口8%之巨。建立一個能夠監測風暴來臨和發出預警的機構顯得相當迫切。

     

    作者︰
    香港天文台前台長岑智明先生
    香港天文台高級科學主任李子祥博士
    香港天文台台長鄭楚明博士


    平均場博奕應用淺談



    平均場博奕(mean field game,MFG)理論專門探討數量龐大的智能體(agent)在競爭環境下所使用的策略。每個智能體都會因應身邊其他智能體所採取的行動而隨之應變,務求令自可獲得最大利益。例如,在股票市場,每位交易者為追求最高回報率,都會先留意其他交易者所採取的策略,再決定買入或賣出若干數量的股票。「平均場」(mean field)一詞本來是物理學術語,意思是大群體裏的單一智能體行為對系統的影響微不足道。在典型的MFG裏,智能體的行為是基於其他智能體的狀態分佈而作出反應,而非個別地針對其他智能體的行為而行動。例如,在購物市場裏,某位客人可以在得知其他客人及賣家的交易資訊後才去購買商品,然而這種做法現實幾乎不可能做到,而且費時失事。相反,在平均場的情境之下,他/她可以只看商品的價格就作決定,令決定的流程變得簡單。在市場裏,價格是由買賣雙方經過互動而得出,因此,它蘊含了市場內所有智能體的狀態及策略的概率分佈。將價格視為平均場,能大大節省決策時間,而它本身亦可算是一種平均場。

     

    作者︰
    香港城市大學數學系助理教授牟宸辰博士


    流言終結者:黑洞篇

    簡介黑洞

    雖然科學家早於18世紀已經猜測到黑洞的存在,但最先在科學上預測到黑洞存在的卻是愛因斯坦的廣義相對論,那是作為愛因斯坦重力場方程式中的一個解。愛因斯坦的相對論大概可以用約翰·惠勒(John Wheeler)的一句話優雅地總結:「時空告訴物質怎樣移動,物質告訴時空怎樣扭曲(Space-time tells matter how to move; matter tells space-time how to curve)」。

    物質會令時空變得扭曲;在黑洞事件視界(event horizon)的周圍,時空扭曲得甚至連光也不能逃逸。這發生在一顆恆星塌縮至一定小的體積時,更準確地說,比史瓦西半徑(Schwarzschild radius)還要小的時候(這裡M代表恆星的質量、c是光速、G是重力常數)。

    讓我們從具體例子看看:如果我們的太陽是一個黑洞的話,它的半徑就會約為2.95公里;相比之下,太陽現時的半徑為696,340公里。事實上,因為太陽的質量相比下實在太微不足道了,所以我們永遠都不用擔心太陽會變成一個黑洞 — 這一定不會發生!

    宇宙裡的黑洞都是從重力塌縮(gravitational collapse)的過程形成的。在一顆瀕死的恆星裡面,較重的元素會進行核聚變,令恆星的內部壓力降低;隨著恆星的壓力降低,引力會令它進一步塌縮,這星體的密度將會變得極高,所產生的重力也自然大得驚人 — 這就是黑洞。修讀高中物理的同學可能記得逃逸速度(escape velocity)這個概念:黑洞的體積極小、質量極大,令逃逸速度比光速還要快,所以沒有東西能逃出黑洞 — 連光也不能。

     

    作者︰
    蔡蒨珩小姐
    《科言》學生編輯
    香港科技大學


  • newsletter (July 2021 – Issue 10)

    newsletter (July 2021 – Issue 10)


    About the Hong Kong Laureate Forum



    Welcome to the July 2021 issue of the newsletter of the Hong Kong Laureate Forum!

    While the inaugural Forum would be deferred for one year to November 2022, our work on fostering exchanges among scientists of different generations, cultures and disciplines; promoting understanding and interests of young generation in various disciplines in science and technology will not slow down. The HKLF is organising a series of pre-Forum events to continue our effort in facilitating networking among young scientists from different parts of the world and to beat the drum for the inaugural Forum. The “Prelude to the Inaugural Forum” would include “Science Exposition”, which showcases the research achievements of Hong Kong; “Masterminds, Masterclasses”, seminars by and dialogues with world-renowned scientists; “Exploring New Horizons”, an opportunity to witness promising scientists at work; “Wonder Women in Science – Inspiring and Empowering the Next Generation”, which showcases and affirms women’s contribution in science as well as promotes women’s wider participation in science. A press event “Beckoning the Inaugural Hong Kong Laureate Forum” will also be held to kick start the inaugural Forum.

    For our online game “Your Fame, Its Name”, which ended on 9 July, we received more than 70 entries in total after two rounds of the Game. The winners were chosen after consolidating the scores by the judging panelists and the votes cast by more than 800 visitors to our Facebook page. Their entries were indeed very interesting and engaging. Once again, congratulations to the winners of the game, who had collected their prizes with glee. Special thanks to the three judging panelists, they are:

    – Mr SHUN Chi-ming, SBS, former Director of the Hong Kong Observatory
    – Dr TONG Shiu-sing Dominic, The Chinese University of Hong Kong
    – Dr HO Koon-sing, the Hong Kong Baptist University

    We will continue to launch interesting and informative science games and promote science in the community.

    Please stay tuned to our website and social media channels for more information on the “Prelude to the Inaugural Forum” and science games!

    Last but not least, the Shaw Laureates 2021 were announced on 1 June 2021 at a press conference held by The Shaw Prize Foundation.

    The Shaw Prize in Astronomy is awarded in equal shares to Prof Victoria M Kaspi of McGill University, Canada and Prof Chryssa Kouveliotou of George Washington University, USA for their contributions to our understanding of magnetars, a class of highly magnetised neutron stars that are linked to a wide range of spectacular, transient astrophysical phenomena. Through the development of new and precise observational techniques, they confirmed the existence of neutron stars with ultra-strong magnetic fields and characterised their physical properties. Their work has established magnetars as a new and important class of astrophysical objects.

    The Shaw Prize in Life Science and Medicine is awarded to Prof Scott D Emr of Cornell University, USA for the landmark discovery of the ESCRT (Endosomal Sorting Complex Required for Transport) pathway, which is essential in diverse processes involving membrane biology, including cell division, cell-surface receptor regulation, viral dissemination, and nerve axon pruning. These processes are central to life, health and disease.

    The Shaw Prize in Mathematical Sciences is awarded in equal shares to Prof Jean-Michel Bismut of Université Paris-Saclay, France and Prof Jeff Cheeger of New York University, USA for their remarkable insights that have transformed, and continue to transform, modern geometry.

    Congratulations to the five Shaw Laureates 2021! The Award Ceremony for The Shaw Prize 2021 will again be presented online this year and is scheduled to be held in October this year. Stay tuned to The Shaw Prize website and social media as well as ours for further information!


    Early History of the Hong Kong Observatory



    The need for an observatory

    Since 1841, Hong Kong became an important port of trade. In order to ensure smooth port operations and safe navigation of ships, there was a need to provide accurate time service. In the last edition of the Hong Kong Laureate Forum Newsletter, Mr SHUN Chi-ming, former Director of the Hong Kong Observatory (HKO), discussed the important role that astronomical observations played in maritime navigation, especially the need for an accurate clock onboard for determining latitude and longitude at sea. Initially, the time service was provided by the Noonday Gun, which was fired daily at noon. However, by 1861, people began to question the accuracy of this method, and there were calls to provide a more accurate time service based on scientific methods.

    Located on the southern coast of China, Hong Kong is susceptible to typhoons between the months of May to November every year. As early as the 18th century, foreign merchants working in Huangpu Port and the ‘Thirteen Factories’ in Guangzhou wrote detailed records of typhoons and their impacts. In July 1841, shortly after the British occupation of Hong Kong, a typhoon almost claimed the lives of Gordon BREMER, Commander-in-chief of the British forces in the area and pivotal figure in the First Opium War, and Charles ELIOT, the first Administrator of Hong Kong. A few decades later in September 1874, one of the strongest typhoons in Hong Kong’s history caused serious damage across Hong Kong and Macau, killing over 2,000 people in Hong Kong and 5,000 people in Macau – approximately 8% of its population. In the aftermath of these disasters, there was an urgent need for an organisation that could predict the arrival of storms and issue warnings.

     

    Authors:
    Mr SHUN Chi-ming, Former Director of the Hong Kong Observatory
    Dr LEE Tsz-cheung, Senior Scientific Officer, Hong Kong Observatory
    Dr CHENG Cho-ming, Director of the Hong Kong Observatory


    A Glimpse into the Applications of Mean Field Games



    Mean field game (MFG) theory studies the strategies of agents of a large population in a competitive environment. Each agent seeks to maximise its own benefit according to the actions of other agents surrounded. For example, in the stock market, each trader buys or sells a certain number of shares based on other traders’ strategies in order to maximise his / her rates of return. The term “mean field” comes from physics, which means that the behaviour of an individual agent in a large population has negligible impact upon the system. In a typical MFG, an agent behaves based on the distribution of the states of other agents instead of reacting upon the behaviour of other agents individually. For instance, in a shopping market, a customer can buy some good after knowing the trading information of other customers and sellers, which is somehow impossible and troublesome. Instead, in a mean field scenario, he / she can decide based only on the price of the good, which simplifies the decision. In the market, the price is formed through the interaction of buyers and sellers. Thus, it encodes the probabilistic distributions of the states and strategies of all the agents in the market. The price, viewed as a mean field, enormously saves the time of making decisions.

     

    Author:
    Dr MOU Chenchen, Assistant Professor, Department of Mathematics, City University of Hong Kong


    MythBusters: Black Holes

    Black Holes: A Brief Introduction

    Although the existence of black holes was first speculated in the 18th century, they were first scientifically predicted by Einstein’s theory of general relativity as a solution to the Einstein field equations. Einstein’s theory of relativity can be elegantly summed up in twelve words from John Wheeler – “Space-time tells matter how to move; matter tells space-time how to curve.”

    Mass bends the fabric of space-time itself; around a black hole’s event horizon, the space-time is bent in a way that even light cannot escape. This occurs when the size of a star collapses to a small enough size – more specifically, smaller than the Schwarzschild radius, . (Here M is the mass of the star, c is the speed of light, and G is the gravitational constant.)

    To put things into perspective, if the Sun were a black hole, it would have a radius of approximately 2.95 km; in comparison, the current radius of the Sun is 696,340 km. Actually, owing to the relatively tiny mass of the Sun, it can never turn into a black hole – so we won’t have to worry about our Sun turning into a black hole any time soon!

    The black holes we can see in the sky are formed by a process known as gravitational collapse. In a dying star, there is a reduction in internal pressure due to the fusing of heavier elements. As the internal pressure continues to decrease, gravity causes the star to further collapse onto itself. Eventually, the density of the star becomes high enough that it creates a very strong gravitational pull – and this is a black hole. You may recall the concept of escape velocity from high school physics; black holes are so small and massive that the escape velocity is greater than the speed of light. Nothing escapes a black hole – not even light.

     

    Author:
    Ms Sonia Choy
    Student Editor, Science Focus
    The Hong Kong University of Science and Technology


  • 流言终结者:黑洞篇

    流言终结者:黑洞篇

    在2019年4月10日,一组科学家完成了壮举:他们成功拍到了黑洞有史以来的第一幅照片。这张得来不易的照片理所当然地占据了全世界报纸的头版,毕竟人类从来也没有想过自己能够拍到黑洞,而且能够把它广传。…

    (more…)

  • 流言終結者:黑洞篇

    流言終結者:黑洞篇

    在2019年4月10日,一組科學家完成了壯舉:他們成功拍到了黑洞有史以來的第一幅照片。這張得來不易的照片理所當然地佔據了全世界報紙的頭版,畢竟人類從來也沒有想過自己能夠拍到黑洞,而且能夠把它廣傳…

    (more…)

  • MythBusters: Black Holes

    MythBusters: Black Holes

    On April 10, 2019, a team of scientists made history by capturing the first ever image of a black hole. This remarkable picture occupied headlines worldwide, and rightfully so – we never thought we would ever be able to capture a black hole in an image that can be passed around the world…

    (more…)

  • 平均场博奕应用浅谈

    平均场博奕应用浅谈

    平均場博奕(mean field game,MFG)理論專門探討數量龐大的智能體(agent)在競爭環境下所使用的策略。…

    (more…)

  • 平均場博奕應用淺談

    平均場博奕應用淺談

    平均場博奕(mean field game,MFG)理論專門探討數量龐大的智能體(agent)在競爭環境下所使用的策略…

    (more…)

  • A Glimpse into the Applications of Mean Field Games

    A Glimpse into the Applications of Mean Field Games

    Mean field game (MFG) theory studies the strategies of agents of a large population in a competitive environment…

    (more…)

  • 香港天文台的早期历史

    香港天文台的早期历史

    香港在1841年開埠以來,不斷發展成為一個重要的貿易港口,要確保港口運作暢順和船隻航行安全,首先必須提供準確的報時服務…

    (more…)

  • 香港天文台的早期歷史

    香港天文台的早期歷史

    香港在1841年開埠以來,不斷發展成為一個重要的貿易港口,要確保港口運作暢順和船隻航行安全,首先必須提供準確的報時服務…

    (more…)