Reducing Ambiguities in Line-based Density Plots by Image-space Colorization

Line-based density plots are used to reduce visual clutter in line charts with a multitude of individual lines. However, these traditional density plots are often perceived ambiguously, which obstructs the user's identification of underlying trends in complex datasets. Thus, we propose a novel image space coloring method for line-based density plots that enhances their interpretability. Our method employs color not only to visually communicate data density but also to highlight similar regions in the plot, allowing users to identify and distinguish trends easily. We achieve this by performing hierarchical clustering based on the lines passing through each region and mapping the identified clusters to the hue circle using circular MDS. Additionally, we propose a heuristic approach to assign each line to the most probable cluster, enabling users to analyze density and individual lines. We motivate our method by conducting a small-scale user study, demonstrating the effectiveness of our method using synthetic and real-world datasets, and providing an interactive online tool for generating colored line-based density plots

The photometric observation of the quasi-simultaneous mutual eclipse and occultation between Europa and Ganymede on 22 August 2021

Mutual events (MEs) are eclipses and occultations among planetary natural satellites. Most of the time, eclipses and occultations occur separately. However, the same satellite pair will exhibit an eclipse and an occultation quasi-simultaneously under particular orbital configurations. This kind of rare event is termed as a quasi-simultaneous mutual event (QSME). During the 2021 campaign of mutual events of jovian satellites, we observed a QSME between Europa and Ganymede. The present study aims to describe and study the event in detail. We observed the QSME with a CCD camera attached to a 300-mm telescope at the Hong Kong Space Museum Sai Kung iObservatory. We obtained the combined flux of Europa and Ganymede from aperture photometry. A geometric model was developed to explain the light curve observed. Our results are compared with theoretical predictions (O-C). We found that our simple geometric model can explain the QSME fairly accurately, and the QSME light curve is a superposition of the light curves of an eclipse and an occultation. Notably, the observed flux drops are within 2.6% of the theoretical predictions. The size of the event central time O-Cs ranges from -14.4 to 43.2 s. Both O-Cs of flux drop and timing are comparable to other studies adopting more complicated models. Given the event rarity, model simplicity and accuracy, we encourage more observations and analysis on QSMEs to improve Solar System ephemerides.Comment: 23 pages, 5 appendixes, 16 figures, 7 table

照顧者實用資訊手冊

手冊源起 香港面對人口高齡化，醫療和福利系統無可避免面臨持續的挑戰。照顧者因壓力問題而引發的家庭悲劇時有發生，反映照顧者自身亦極需要社會的重視和支援。 現時照顧者人數眾多，當中不乏配偶、父母、子女、女婿、媳婦，對長者照顧及社會無酬的付出，確實值得社會的認同和肯定。然而，儘管本港為長者及照顧者提供不少支援服務，由於不同的原因，照顧者似乎未有善用現有的服務，常常需要一力承擔所有照顧的責任，這無疑增加了他們的壓力。 照顧者需求多樣性 照顧者有不同種類，所需要的服務或支援亦有所不同。例如：「新手照顧者」剛開始接觸照顧工作，需要盡快提升日常護理和相關的疾病知識，以及獲得合適的離院/復康服務支援。「隱蔽照顧者」一直承擔照顧工作但沒有接受任何支援，因此，他們需要的是服務提供者/鄰里的主動接觸，並被轉介合適的照顧服務，以分擔他們部分照顧工作。「高危照顧者」幾乎長時間被照顧的工作佔據了其生活，他們需要的是喘息空間和暫託服務，甚至可能是情緒支援。即使「資深的照顧者」也可能需要喘息或暫託的支援服務去減輕壓力；而結束了照顧工作的「畢業照顧者」，無論是情緒的支援，還是重新規劃財務與就業的安排，都有非常實際的需求。基於照顧者的不同需要，照顧者的支援和服務也是多樣化，如何讓不同種類的照顧者能夠輕易了解現有的社區支援服務、可考慮甚麼因素選取相關服務、如何獲取所需的支援包括申領經濟支援或預早準備長期護理開支、如何自強增值等，都是這本手冊希望解答的問題。 手冊的目的 編製這本手冊的目的就是要減少照顧者四處尋找資訊的麻煩，提供一個整全且易於瀏覽的資訊來源。本手冊主要有兩大目標：其一，幫助照顧者認識不同的服務和資源，積極尋求援助；其二是一站式提供豐富的資訊服務，提升照顧者的能力和平衡身心健康。 手冊的意義 此手冊的社會意義是期望提高大眾對照顧者需要的關注，並引導更多的行動以支援照顧者。如果您的親友是照顧者，又或您認識的朋友甚至鄰居正面對照顧家人的困難，您可以主動伸出援手，又或利用這本手冊作為啟示，向他們介紹相關的服務。 另外，這本手冊可以視作為支援照顧者的工具，讓照顧者明白在承擔照顧家人的重任時並不需要孤軍奮戰，也可以善用社區提供的各種資源和服務。 手冊架構 本手冊由四個主要部分組成，每部分都專注於特定的主題，旨在提供照顧者的全方位支援和資訊，幫助他們在面對挑戰時能夠有所依賴，並從中獲得力量： 第一部分主要提供基礎知識，其中包括不同種類的照顧者的介紹、四種長者常見疾病（包括認知障礙、中風、老年抑鬱和癌症）的病徵說明、以及照顧者可能面臨的壓力與「喘息服務」的重要性。第二部分專注介紹長者常用的社區及健康服務。我們按照地區將服務機構進行了分類，羅列「認知障礙、中風、老年抑鬱、癌症」常用的服務機構，此外，我們還提供家居安全、樂齡科技租賃服務，以及財務支援等相關建議。第三部分將焦點重新放回照顧者身上，提供了支援照顧者的社福機構介紹、照顧者同路人的心得分享，以及照顧者的培訓資訊，旨在幫助照顧者在面對困難時能自強不息。最後，在本手冊的結尾部分，我們特別邀請了四位專家學者就照顧者政策提出見解和建議，為加強照顧者支援服務提供新思路。 如果按持份者來分類，手冊的四個部分的重點如下： 第一部分：照顧者的基礎知識 ◎ 針對預備照顧者、新手以及隱蔽照顧者，讓他們了解照顧者的角色和需要；照顧體弱長者的基礎知識，並提供應對壓力的建議，包括自我照顧和喘息服務等。 第二部分：照顧者支援 ◎ 針對所有護老者，提供長者常用的社區服務、健康服務和支援計劃，包括暫託、住宿、護送及陪診、善別支援、情緒支援、復康用品津貼及租賃的支援計劃，以及財務策劃師提供的理財貼士。 第三部分：照顧者自強 ◎ 針對照顧者，資訊包括不同的照顧者支援組織、同路人和畢業照顧者的經驗心得、培訓課程，以及實用的電子資訊平台推介。 第四部分：對照顧者支援政策的看法和展望 ◎ 針對服務提供者、政策倡議者及制定者，提供專家學者對照顧者服務及政策的未來發展方向的看法和建議，以期引發更多關於「如何為照顧者提供更好支持」的討論。 給讀者的使用指引 本手冊內容十分豐富，讀者可以先瀏覽目錄，選擇與您相關的部分進行細讀。對於新手照顧者或剛接觸/關注護老服務的人士(例如：學生、社區人士)，我們建議您可以參考手冊第24-33頁「給照顧者的智慧錦囊」的個案，了解不同照顧者可能面對的情境，這可能會給您一點概念，讓您可以考慮尋求哪些支援服務，又或您身邊照顧者朋友有哪些需要，以及如何協助他們獲取所需要的支援。我們深知閱讀本手冊時，您可能會遇到一些不明白的地方，請不必感到困惑。您可以嘗試找身邊的朋友、鄰居或社會服務機構的工作人員一起閱讀，或者向本中心的職員進行查詢。 此外，為方便讀者可以隨時隨地閱讀而不需要攜帶整本手冊，我們為本手冊設立了一個專屬網頁，免費下載整本手冊或某些章節內容。 希望您在閱讀的過程中能找到有用的資訊，並能從中獲得實際的幫助。https://commons.ln.edu.hk/apias_guide/1009/thumbnail.jp

Multi-class inverted stippling

We introduce inverted stippling, a method to mimic an inversion technique used by artists when performing stippling. To this end, we extend Linde-Buzo-Gray (LBG) stippling to multi-class LBG (MLBG) stippling with multiple layers. MLBG stippling couples the layers stochastically to optimize for per-layer and overall blue-noise properties. We propose a stipple-based filling method to generate solid color backgrounds for inverting areas. Our experiments demonstrate the effectiveness of MLBG in terms of reducing overlapping and intensity accuracy. In addition, we showcase MLBG with color stippling and dynamic multi-class blue-noise sampling, which is possible due to its support for temporal coherence.publishe

A Two-Phase Space Resection Model for Accurate Topographic Reconstruction from Lunar Imagery with PushbroomScanners

Exterior orientation parameters’ (EOP) estimation using space resection plays an important role in topographic reconstruction for push broom scanners. However, existing models of space resection are highly sensitive to errors in data. Unfortunately, for lunar imagery, the altitude data at the ground control points (GCPs) for space resection are error-prone. Thus, existing models fail to produce reliable EOPs. Motivated by a finding that for push broom scanners, angular rotations of EOPs can be estimated independent of the altitude data and only involving the geographic data at the GCPs, which are already provided, hence, we divide the modeling of space resection into two phases. Firstly, we estimate the angular rotations based on the reliable geographic data using our proposed mathematical model. Then, with the accurate angular rotations, the collinear equations for space resection are simplified into a linear problem, and the global optimal solution for the spatial position of EOPs can always be achieved. Moreover, a certainty term is integrated to penalize the unreliable altitude data for increasing the error tolerance. Experimental results evidence that our model can obtain more accurate EOPs and topographic maps not only for the simulated data, but also for the real data from Chang’E-1, compared to the existing space resection model

Smoking, Alcohol Drinking and Non-Fatal Coronary Heart Disease in Hong Kong Chinese

Purpose: To examine whether smoking, alcohol drinking and other risk factors were associated with non-fatal coronary heart disease (CHD) in Hong Kong Chinese. Methods: A case control study was carried out with 598 CHD hospital cases (431 men, 167 women) and 1100 community controls (663 men, 437 women). Standardized questionnaires were used and blood lipids were measured using standard methods. Results: Stepwise logistic regression models showed adjusted odds ratios (AOR) of 3.36 [95% confidence interval (CI): 2.35 to 4.81] for smoking and 0.32 (95% CI: 0.22 to 0.45) for alcohol drinking in men, and 6.50 (95% CI: 2.61 to 16.19) and 0.15 (95% CI: 0.08 to 0.30), respectively, in women. The OR increased with decreasing levels of high-density lipoprotein cholesterol (HDL) and increasing levels of triglycerides. No patterns were observed for body mass index (BMI), total and low-density lipoprotein cholesterol (LDL). The protective effect of drinking was observed for different types of drinks and frequency of drinking, although few drank alcohol more than 3 days per week. Conclusions: Smoking was a strong risk factor and moderate alcohol drinking was a protective factor for CHD, and low HDL and high triglyceride levels were important risk factors in Hong Kong Chinese

Genomic Investigation of <i>Salmonella</i> Typhi in Hong Kong Revealing the Predominance of Genotype 3.2.2 and the First Case of an Extensively Drug-Resistant H58 Genotype

Typhoid fever is a notable disease in Hong Kong. We noticed two local cases of typhoid fever caused by Salmonella Typhi within a two-week period in late 2022, which had no apparent epidemiological linkage except for residing in the same region of Hong Kong. A phylogenetic study of Salmonella Typhi isolates from Hong Kong Island from 2020 to 2022 was performed, including a whole-genome analysis, the typing of plasmids, and the analysis of antibiotic-resistance genes (ARGs), to identify the dominant circulating strain and the spread of ARGs. A total of seven isolates, from six local cases and an imported case, were identified from positive blood cultures in two hospitals in Hong Kong. Five antibiotic-sensitive strains of genotype 3.2.2 were found, which clustered with another 30 strains originating from Southeast Asia. Whole-genome sequencing revealed clonal transmission between the two index cases. The remaining two local cases belong to genotype 2.3.4 and genotype 4.3.1.1.P1 (also known as the H58 lineage). The genotype 4.3.1.1.P1 strain has an extensively drug-resistant (XDR) phenotype (co-resistance to ampicillin, chloramphenicol, ceftriaxone, ciprofloxacin, and co-trimoxazole). Although the majority of local strains belong to the non-H58 genotype 3.2.2 with a low degree of antibiotic resistance, the introduction of XDR strains with the global dissemination of the H58 lineage remains a concern